TY  - JOUR
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil
AU  - Ivanovski, Valentin N.
AU  - Toprek, Dragan
AU  - Umićević, Ana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11641
AB  - In order to provide insight into the influence of co-doping with boron (B) and transition metals (TM = Pt, Ta, V) on the photoactivity of anatase TiO2 , the electronic, structural and optical characteristics of the mentioned co-doped systems were studied using density functional theory calculations and the modified Becke–Johnson exchange potential. For each transition metal two cases were considered, with B atom either replacing O atom (B-substitutional) or imbedding interstitially (B-interstitial) into TiO2 lattice. The calculations showed that the co-doping is more favorable for the B-interstitial systems than for the B-substitutional ones and under the O-rich conditions. For the B-substitutional cases a slight decrease of the band gap is observed. In contrast, the results obtained for the B-interstitial systems exhibited no band gap narrowing. However, in these systems, the occurrence of localized states within the band gap is noticed, which could improve visible light absorption through a two-step optical transition.
T2  - Physica B: Condensed Matter
T1  - Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping
VL  - 670
SP  - 415358
DO  - 10.1016/j.physb.2023.415358
ER  - 

@article{
author = "Belošević-Čavor, Jelena and Koteski, Vasil and Ivanovski, Valentin N. and Toprek, Dragan and Umićević, Ana",
year = "2023",
abstract = "In order to provide insight into the influence of co-doping with boron (B) and transition metals (TM = Pt, Ta, V) on the photoactivity of anatase TiO2 , the electronic, structural and optical characteristics of the mentioned co-doped systems were studied using density functional theory calculations and the modified Becke–Johnson exchange potential. For each transition metal two cases were considered, with B atom either replacing O atom (B-substitutional) or imbedding interstitially (B-interstitial) into TiO2 lattice. The calculations showed that the co-doping is more favorable for the B-interstitial systems than for the B-substitutional ones and under the O-rich conditions. For the B-substitutional cases a slight decrease of the band gap is observed. In contrast, the results obtained for the B-interstitial systems exhibited no band gap narrowing. However, in these systems, the occurrence of localized states within the band gap is noticed, which could improve visible light absorption through a two-step optical transition.",
journal = "Physica B: Condensed Matter",
title = "Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping",
volume = "670",
pages = "415358",
doi = "10.1016/j.physb.2023.415358"
}

Belošević-Čavor, J., Koteski, V., Ivanovski, V. N., Toprek, D.,& Umićević, A.. (2023). Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping. in Physica B: Condensed Matter, 670, 415358.
https://doi.org/10.1016/j.physb.2023.415358

Belošević-Čavor J, Koteski V, Ivanovski VN, Toprek D, Umićević A. Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping. in Physica B: Condensed Matter. 2023;670:415358.
doi:10.1016/j.physb.2023.415358 .

Belošević-Čavor, Jelena, Koteski, Vasil, Ivanovski, Valentin N., Toprek, Dragan, Umićević, Ana, "Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping" in Physica B: Condensed Matter, 670 (2023):415358,
https://doi.org/10.1016/j.physb.2023.415358 . .

TY  - CONF
AU  - Umićević, Ana
AU  - Banerjee, D.
AU  - Dey, C. C.
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil
AU  - Ivanovski, Valentin
AU  - Toprek, Dragan
AU  - Kapidžić, Ana
AU  - Wasim Raja, Sk.
AU  - Dey Chaudhuri, S.
AU  - Blanuša, Jovan
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12110
AB  - Laves phases (AB2) are alloys whose metal hydrides have been proposed to improve the energy density of Ni-MH batteries. In case of ZrV2-based battery materials, various amounts of different modifiers, such as Ti and Ni are used to improve their performance. The influence of Ni modifier in ZrV2 C15 Laves phase was investigated at atomic level by the 181TaPerturbed Angular Correlation (PAC) measurements of Zr(V0.33Ni0.67)2, Zr(V0.33Ni0.67)2.4 and Zr27V18Ni55 compounds. The dominant C15-type crystallographic structures were found in all samples by the X-ray diffraction, with the minority presence of other phases, mostly various oxides. The 181Ta-PAC preliminary results showed four different electric quadrupole interactions which give similar values for electric field gradients and non-zero asymmetry parameters in all investigated compounds.
C3  - HYPERFINE2023 : International Conference on Hyperfine Interactions and their Applications : Program & Abstracts
T1  - Perturbed angular correlation study of zirconium based C15 laves phases
SP  - 72
EP  - 72
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12110
ER  - 

@conference{
author = "Umićević, Ana and Banerjee, D. and Dey, C. C. and Belošević-Čavor, Jelena and Koteski, Vasil and Ivanovski, Valentin and Toprek, Dragan and Kapidžić, Ana and Wasim Raja, Sk. and Dey Chaudhuri, S. and Blanuša, Jovan",
year = "2023",
abstract = "Laves phases (AB2) are alloys whose metal hydrides have been proposed to improve the energy density of Ni-MH batteries. In case of ZrV2-based battery materials, various amounts of different modifiers, such as Ti and Ni are used to improve their performance. The influence of Ni modifier in ZrV2 C15 Laves phase was investigated at atomic level by the 181TaPerturbed Angular Correlation (PAC) measurements of Zr(V0.33Ni0.67)2, Zr(V0.33Ni0.67)2.4 and Zr27V18Ni55 compounds. The dominant C15-type crystallographic structures were found in all samples by the X-ray diffraction, with the minority presence of other phases, mostly various oxides. The 181Ta-PAC preliminary results showed four different electric quadrupole interactions which give similar values for electric field gradients and non-zero asymmetry parameters in all investigated compounds.",
journal = "HYPERFINE2023 : International Conference on Hyperfine Interactions and their Applications : Program & Abstracts",
title = "Perturbed angular correlation study of zirconium based C15 laves phases",
pages = "72-72",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12110"
}

Umićević, A., Banerjee, D., Dey, C. C., Belošević-Čavor, J., Koteski, V., Ivanovski, V., Toprek, D., Kapidžić, A., Wasim Raja, Sk., Dey Chaudhuri, S.,& Blanuša, J.. (2023). Perturbed angular correlation study of zirconium based C15 laves phases. in HYPERFINE2023 : International Conference on Hyperfine Interactions and their Applications : Program & Abstracts, 72-72.
https://hdl.handle.net/21.15107/rcub_vinar_12110

Umićević A, Banerjee D, Dey CC, Belošević-Čavor J, Koteski V, Ivanovski V, Toprek D, Kapidžić A, Wasim Raja S, Dey Chaudhuri S, Blanuša J. Perturbed angular correlation study of zirconium based C15 laves phases. in HYPERFINE2023 : International Conference on Hyperfine Interactions and their Applications : Program & Abstracts. 2023;:72-72.
https://hdl.handle.net/21.15107/rcub_vinar_12110 .

Umićević, Ana, Banerjee, D., Dey, C. C., Belošević-Čavor, Jelena, Koteski, Vasil, Ivanovski, Valentin, Toprek, Dragan, Kapidžić, Ana, Wasim Raja, Sk., Dey Chaudhuri, S., Blanuša, Jovan, "Perturbed angular correlation study of zirconium based C15 laves phases" in HYPERFINE2023 : International Conference on Hyperfine Interactions and their Applications : Program & Abstracts (2023):72-72,
https://hdl.handle.net/21.15107/rcub_vinar_12110 .

TY  - CONF
AU  - Ivanovski, Valentin
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil
AU  - Umićević, Ana
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12796
AB  - In the present work, the electronic and optical properties of (B, TM) co-doped (
TM = Pt, Ta, V) anatase TiO 2 were investigated using modified density functional
theory (DFT) calculations, in order to provide insight into the synergistic effect of
co-doping with various elements on the photoactivity of TiO 2. We considered two
combinations for each co-doped sample, with TM atom replacing Ti atom and B
atom either replacing O atom or embedding interstitially into TiO 2 lattice. The
calculations showed that for all studied transition metals, the co-doping is more
favorable in the case of interstitially doped boron than for the substitutional one
and under the O-rich conditions. For the co-doped systems with B atom substitutionally replacing O atom, a small reduction of the band gap is observed in all the
investigated cases. In contrast, the results obtained for the co-doped systems with
boron embedded interstitially into TiO 2 lattice, exhibited no band gap narrowing.
However, in these systems, the doping induced localized states within the band gap,
which could enhance visible light absorption through a two step optical transition
from the valence to conduction band
C3  - BPU11 : 11th International Conference of the Balkan Physical Union : Book of abstracts
T1  - Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping
SP  - 199
EP  - 199
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12796
ER  - 

@conference{
author = "Ivanovski, Valentin and Belošević-Čavor, Jelena and Koteski, Vasil and Umićević, Ana",
year = "2022",
abstract = "In the present work, the electronic and optical properties of (B, TM) co-doped (
TM = Pt, Ta, V) anatase TiO 2 were investigated using modified density functional
theory (DFT) calculations, in order to provide insight into the synergistic effect of
co-doping with various elements on the photoactivity of TiO 2. We considered two
combinations for each co-doped sample, with TM atom replacing Ti atom and B
atom either replacing O atom or embedding interstitially into TiO 2 lattice. The
calculations showed that for all studied transition metals, the co-doping is more
favorable in the case of interstitially doped boron than for the substitutional one
and under the O-rich conditions. For the co-doped systems with B atom substitutionally replacing O atom, a small reduction of the band gap is observed in all the
investigated cases. In contrast, the results obtained for the co-doped systems with
boron embedded interstitially into TiO 2 lattice, exhibited no band gap narrowing.
However, in these systems, the doping induced localized states within the band gap,
which could enhance visible light absorption through a two step optical transition
from the valence to conduction band",
journal = "BPU11 : 11th International Conference of the Balkan Physical Union : Book of abstracts",
title = "Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping",
pages = "199-199",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12796"
}

Ivanovski, V., Belošević-Čavor, J., Koteski, V.,& Umićević, A.. (2022). Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping. in BPU11 : 11th International Conference of the Balkan Physical Union : Book of abstracts, 199-199.
https://hdl.handle.net/21.15107/rcub_vinar_12796

Ivanovski V, Belošević-Čavor J, Koteski V, Umićević A. Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping. in BPU11 : 11th International Conference of the Balkan Physical Union : Book of abstracts. 2022;:199-199.
https://hdl.handle.net/21.15107/rcub_vinar_12796 .

Ivanovski, Valentin, Belošević-Čavor, Jelena, Koteski, Vasil, Umićević, Ana, "Tailoring the photocatalytic properties of anatase TiO2 by B–TM (TM = Pt, Ta, V) co-doping" in BPU11 : 11th International Conference of the Balkan Physical Union : Book of abstracts (2022):199-199,
https://hdl.handle.net/21.15107/rcub_vinar_12796 .

TY  - JOUR
AU  - Liu, Yu
AU  - Wang, Aifeng
AU  - Ivanovski, Valentin N.
AU  - Du, Qianheng
AU  - Koteski, Vasil J.
AU  - Petrović, Čedomir
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10174
AB  - We report thermoelectric studies of FeS1-xSex (x=0,0.06) superconducting single crystals that feature high irreversibility fields and critical current density Jc comparable to materials with much higher superconducting critical temperatures (Tc's). The ratio of Tc to the Fermi temperature TF is very small, indicating weak electronic correlations. With a slight selenium substitution on sulfur site in FeS both Tc/TF and the effective mass m∗ rise considerably, implying increase in electronic correlation of the bulk conducting states. The first-principle calculations show rise of the density of states at the Fermi level in FeS0.94Se0.06 when compared to FeS, which is related not only to Fe but also to chalcogen-derived electronic states.
T2  - Physical Review B
T1  - Thermoelectricity and electronic correlation enhancement in FeS by light Se doping
VL  - 105
IS  - 4
SP  - 045133
DO  - 10.1103/PhysRevB.105.045133
ER  - 

@article{
author = "Liu, Yu and Wang, Aifeng and Ivanovski, Valentin N. and Du, Qianheng and Koteski, Vasil J. and Petrović, Čedomir",
year = "2022",
abstract = "We report thermoelectric studies of FeS1-xSex (x=0,0.06) superconducting single crystals that feature high irreversibility fields and critical current density Jc comparable to materials with much higher superconducting critical temperatures (Tc's). The ratio of Tc to the Fermi temperature TF is very small, indicating weak electronic correlations. With a slight selenium substitution on sulfur site in FeS both Tc/TF and the effective mass m∗ rise considerably, implying increase in electronic correlation of the bulk conducting states. The first-principle calculations show rise of the density of states at the Fermi level in FeS0.94Se0.06 when compared to FeS, which is related not only to Fe but also to chalcogen-derived electronic states.",
journal = "Physical Review B",
title = "Thermoelectricity and electronic correlation enhancement in FeS by light Se doping",
volume = "105",
number = "4",
pages = "045133",
doi = "10.1103/PhysRevB.105.045133"
}

Liu, Y., Wang, A., Ivanovski, V. N., Du, Q., Koteski, V. J.,& Petrović, Č.. (2022). Thermoelectricity and electronic correlation enhancement in FeS by light Se doping. in Physical Review B, 105(4), 045133.
https://doi.org/10.1103/PhysRevB.105.045133

Liu Y, Wang A, Ivanovski VN, Du Q, Koteski VJ, Petrović Č. Thermoelectricity and electronic correlation enhancement in FeS by light Se doping. in Physical Review B. 2022;105(4):045133.
doi:10.1103/PhysRevB.105.045133 .

Liu, Yu, Wang, Aifeng, Ivanovski, Valentin N., Du, Qianheng, Koteski, Vasil J., Petrović, Čedomir, "Thermoelectricity and electronic correlation enhancement in FeS by light Se doping" in Physical Review B, 105, no. 4 (2022):045133,
https://doi.org/10.1103/PhysRevB.105.045133 . .

TY  - JOUR
AU  - Kapidžić, Ana
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10205
AB  - By means of a density functional theory (DFT) based augmented plane waves plus local orbitals (APW ​+ ​lo) method, we study the electric field gradients (EFG) in Ta and Cd-doped Zr–Al intermetallics. Comparing the obtained results with the experimental data obtained from the perturbed angular correlation (PAC) measurements, we conclude that Ta atoms always replace Zr in all the investigated compounds. Our results confirmed the previous experimental assumption that Cd substitutes exclusively for Al in ZrAl3 and Zr2Al3. In the case of Zr2Al our calculations suggest that Cd can probably substitute on both Zr and Al lattice sites, while in Zr3Al, it is most likely to occupy Al position. The effects of the distance between the impurity atoms in the supercells and the deviation of the c/a ratio are also discussed.
T2  - Journal of Solid State Chemistry
T2  - Journal of Solid State ChemistryJournal of Solid State Chemistry
T1  - Zirconium aluminides studied with first principles calculations: Hyperfine interactions and site preference of dopants
VL  - 310
SP  - 123042
DO  - 10.1016/j.jssc.2022.123042
ER  - 

@article{
author = "Kapidžić, Ana and Belošević-Čavor, Jelena and Koteski, Vasil J.",
year = "2022",
abstract = "By means of a density functional theory (DFT) based augmented plane waves plus local orbitals (APW ​+ ​lo) method, we study the electric field gradients (EFG) in Ta and Cd-doped Zr–Al intermetallics. Comparing the obtained results with the experimental data obtained from the perturbed angular correlation (PAC) measurements, we conclude that Ta atoms always replace Zr in all the investigated compounds. Our results confirmed the previous experimental assumption that Cd substitutes exclusively for Al in ZrAl3 and Zr2Al3. In the case of Zr2Al our calculations suggest that Cd can probably substitute on both Zr and Al lattice sites, while in Zr3Al, it is most likely to occupy Al position. The effects of the distance between the impurity atoms in the supercells and the deviation of the c/a ratio are also discussed.",
journal = "Journal of Solid State Chemistry, Journal of Solid State ChemistryJournal of Solid State Chemistry",
title = "Zirconium aluminides studied with first principles calculations: Hyperfine interactions and site preference of dopants",
volume = "310",
pages = "123042",
doi = "10.1016/j.jssc.2022.123042"
}

Kapidžić, A., Belošević-Čavor, J.,& Koteski, V. J.. (2022). Zirconium aluminides studied with first principles calculations: Hyperfine interactions and site preference of dopants. in Journal of Solid State Chemistry, 310, 123042.
https://doi.org/10.1016/j.jssc.2022.123042

Kapidžić A, Belošević-Čavor J, Koteski VJ. Zirconium aluminides studied with first principles calculations: Hyperfine interactions and site preference of dopants. in Journal of Solid State Chemistry. 2022;310:123042.
doi:10.1016/j.jssc.2022.123042 .

Kapidžić, Ana, Belošević-Čavor, Jelena, Koteski, Vasil J., "Zirconium aluminides studied with first principles calculations: Hyperfine interactions and site preference of dopants" in Journal of Solid State Chemistry, 310 (2022):123042,
https://doi.org/10.1016/j.jssc.2022.123042 . .

TY  - JOUR
AU  - Liu, Yu
AU  - Tong, Xiao
AU  - Ivanovski, Valentin N.
AU  - Hu, Zhixiang
AU  - Leshchev, Denis
AU  - Zhu, Xiangde
AU  - Lei, Hechang
AU  - Stavitski, Eli
AU  - Attenkofer, Klaus
AU  - Koteski, Vasil J.
AU  - Petrović, Čedomir
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10479
AB  - Charge density waves (CDWs) with superconductivity, competing Fermi surface instabilities, and collective orders have captured much interest in two-dimensional van der Waals (vdW) materials. Understanding the CDW suppression mechanism, its connection to the emerging superconducting state, and electronic correlations provides opportunities for engineering the electronic properties of vdW heterostructures and thin-film devices. Using a combination of the thermal transport, x-ray photoemission spectroscopy, Raman measurements, and first-principles calculations, we observe an increase in electronic correlations of the conducting states as the CDW is suppressed in ZrTe3 with 5% Cu and Ni intercalation in the vdW gap. As superconductivity emerges, intercalation brings not only decoupling of quasi-one-dimensional conduction electrons with phonons as a consequence of intercalation-induced lattice expansion but also a drastic increase in Zr2+ at the expense of Zr4+ metal atoms. These observations not only demonstrate the potential of atomic intercalates in the vdW gap for ground-state tuning but also illustrate the crucial role of the Zr metal valence in the formation of collective electronic orders.
T2  - Physical Review B
T1  - Enhanced superconductivity and electron correlations in intercalated ZrTe3
VL  - 106
IS  - 16
SP  - 165113
DO  - 10.1103/PhysRevB.106.165113
ER  - 

@article{
author = "Liu, Yu and Tong, Xiao and Ivanovski, Valentin N. and Hu, Zhixiang and Leshchev, Denis and Zhu, Xiangde and Lei, Hechang and Stavitski, Eli and Attenkofer, Klaus and Koteski, Vasil J. and Petrović, Čedomir",
year = "2022",
abstract = "Charge density waves (CDWs) with superconductivity, competing Fermi surface instabilities, and collective orders have captured much interest in two-dimensional van der Waals (vdW) materials. Understanding the CDW suppression mechanism, its connection to the emerging superconducting state, and electronic correlations provides opportunities for engineering the electronic properties of vdW heterostructures and thin-film devices. Using a combination of the thermal transport, x-ray photoemission spectroscopy, Raman measurements, and first-principles calculations, we observe an increase in electronic correlations of the conducting states as the CDW is suppressed in ZrTe3 with 5% Cu and Ni intercalation in the vdW gap. As superconductivity emerges, intercalation brings not only decoupling of quasi-one-dimensional conduction electrons with phonons as a consequence of intercalation-induced lattice expansion but also a drastic increase in Zr2+ at the expense of Zr4+ metal atoms. These observations not only demonstrate the potential of atomic intercalates in the vdW gap for ground-state tuning but also illustrate the crucial role of the Zr metal valence in the formation of collective electronic orders.",
journal = "Physical Review B",
title = "Enhanced superconductivity and electron correlations in intercalated ZrTe3",
volume = "106",
number = "16",
pages = "165113",
doi = "10.1103/PhysRevB.106.165113"
}

Liu, Y., Tong, X., Ivanovski, V. N., Hu, Z., Leshchev, D., Zhu, X., Lei, H., Stavitski, E., Attenkofer, K., Koteski, V. J.,& Petrović, Č.. (2022). Enhanced superconductivity and electron correlations in intercalated ZrTe3. in Physical Review B, 106(16), 165113.
https://doi.org/10.1103/PhysRevB.106.165113

Liu Y, Tong X, Ivanovski VN, Hu Z, Leshchev D, Zhu X, Lei H, Stavitski E, Attenkofer K, Koteski VJ, Petrović Č. Enhanced superconductivity and electron correlations in intercalated ZrTe3. in Physical Review B. 2022;106(16):165113.
doi:10.1103/PhysRevB.106.165113 .

Liu, Yu, Tong, Xiao, Ivanovski, Valentin N., Hu, Zhixiang, Leshchev, Denis, Zhu, Xiangde, Lei, Hechang, Stavitski, Eli, Attenkofer, Klaus, Koteski, Vasil J., Petrović, Čedomir, "Enhanced superconductivity and electron correlations in intercalated ZrTe3" in Physical Review B, 106, no. 16 (2022):165113,
https://doi.org/10.1103/PhysRevB.106.165113 . .

TY  - JOUR
AU  - Toprek, Dragan
AU  - Koteski, Vasil J.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9139
AB  - In this paper we studied the effects of the concentration of W as a doped atom on the V lattice site on the electronic and optical properties of tetragonal zircon-type BiVO4 structure. The calculations were performed by the first-principles density functional theory WIEN2k code. The doping strategy was targeting V atoms substituted by W atoms using the same lattice parameters as pure BiVO4 structure. To avoid the self interaction of impurities, the supercell method was adopted ensuring a sufficient length between the impurities in all directions. For all considered concentrations, the optical properties in the visible light range of λ≥550nm are improved over the undoped BiVO4. © 2021 Elsevier B.V.
T2  - Materials Chemistry and Physics
T1  - Improving the photocatalytic activity of tetragonal BiVO4 with zircon-type structure through W doping; Ab initio calculations
VL  - 264
SP  - 124439
DO  - 10.1016/j.matchemphys.2021.124439
ER  - 

@article{
author = "Toprek, Dragan and Koteski, Vasil J.",
year = "2021",
abstract = "In this paper we studied the effects of the concentration of W as a doped atom on the V lattice site on the electronic and optical properties of tetragonal zircon-type BiVO4 structure. The calculations were performed by the first-principles density functional theory WIEN2k code. The doping strategy was targeting V atoms substituted by W atoms using the same lattice parameters as pure BiVO4 structure. To avoid the self interaction of impurities, the supercell method was adopted ensuring a sufficient length between the impurities in all directions. For all considered concentrations, the optical properties in the visible light range of λ≥550nm are improved over the undoped BiVO4. © 2021 Elsevier B.V.",
journal = "Materials Chemistry and Physics",
title = "Improving the photocatalytic activity of tetragonal BiVO4 with zircon-type structure through W doping; Ab initio calculations",
volume = "264",
pages = "124439",
doi = "10.1016/j.matchemphys.2021.124439"
}

Toprek, D.,& Koteski, V. J.. (2021). Improving the photocatalytic activity of tetragonal BiVO4 with zircon-type structure through W doping; Ab initio calculations. in Materials Chemistry and Physics, 264, 124439.
https://doi.org/10.1016/j.matchemphys.2021.124439

Toprek D, Koteski VJ. Improving the photocatalytic activity of tetragonal BiVO4 with zircon-type structure through W doping; Ab initio calculations. in Materials Chemistry and Physics. 2021;264:124439.
doi:10.1016/j.matchemphys.2021.124439 .

Toprek, Dragan, Koteski, Vasil J., "Improving the photocatalytic activity of tetragonal BiVO4 with zircon-type structure through W doping; Ab initio calculations" in Materials Chemistry and Physics, 264 (2021):124439,
https://doi.org/10.1016/j.matchemphys.2021.124439 . .

TY  - JOUR
AU  - Tian, Jianjun
AU  - Ivanovski, Valentin N.
AU  - Abeykoon, Milinda
AU  - Martin, Rodica M.
AU  - Baranets, Sviatoslav
AU  - Martin, Catalin
AU  - Liu, Yu
AU  - Du, Qianheng
AU  - Wang, Aifeng
AU  - Chen, Shuzhang
AU  - Tong, Xiao
AU  - Zhang, Weifeng
AU  - Bobev, Svilen
AU  - Koteski, Vasil J.
AU  - Petrović, Čedomir
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10108
AB  - Transition metal dichalcogenides attract considerable attention due to a variety of interesting properties, including long-range magnetism in nanocrystals. Here we investigate the magnetic, thermal, and electrical properties of an FeTe2 single crystal with iron vacancy defects. Magnetic measurements show a paramagnetic state and the absence of magnetic order with low anisotropy in the magnetic susceptibility. Fe 3d orbitals are well hybridized, contributing to the bad metal electrical resistivity. Observed thermal conductivity values below room temperature are rather low and comparable to those of high-performance thermoelectric materials. Our results indicate that FeTe2 can form in a highly defective marcasite crystal structure which can be exploited in future materials design.
T2  - Physical Review B
T1  - Absence of long-range magnetic order in Fe1−δ Te2  (δ ≈ 0.1) crystals
VL  - 104
IS  - 22
SP  - 224109
DO  - 10.1103/PhysRevB.104.224109
ER  - 

@article{
author = "Tian, Jianjun and Ivanovski, Valentin N. and Abeykoon, Milinda and Martin, Rodica M. and Baranets, Sviatoslav and Martin, Catalin and Liu, Yu and Du, Qianheng and Wang, Aifeng and Chen, Shuzhang and Tong, Xiao and Zhang, Weifeng and Bobev, Svilen and Koteski, Vasil J. and Petrović, Čedomir",
year = "2021",
abstract = "Transition metal dichalcogenides attract considerable attention due to a variety of interesting properties, including long-range magnetism in nanocrystals. Here we investigate the magnetic, thermal, and electrical properties of an FeTe2 single crystal with iron vacancy defects. Magnetic measurements show a paramagnetic state and the absence of magnetic order with low anisotropy in the magnetic susceptibility. Fe 3d orbitals are well hybridized, contributing to the bad metal electrical resistivity. Observed thermal conductivity values below room temperature are rather low and comparable to those of high-performance thermoelectric materials. Our results indicate that FeTe2 can form in a highly defective marcasite crystal structure which can be exploited in future materials design.",
journal = "Physical Review B",
title = "Absence of long-range magnetic order in Fe1−δ Te2  (δ ≈ 0.1) crystals",
volume = "104",
number = "22",
pages = "224109",
doi = "10.1103/PhysRevB.104.224109"
}

Tian, J., Ivanovski, V. N., Abeykoon, M., Martin, R. M., Baranets, S., Martin, C., Liu, Y., Du, Q., Wang, A., Chen, S., Tong, X., Zhang, W., Bobev, S., Koteski, V. J.,& Petrović, Č.. (2021). Absence of long-range magnetic order in Fe1−δ Te2  (δ ≈ 0.1) crystals. in Physical Review B, 104(22), 224109.
https://doi.org/10.1103/PhysRevB.104.224109

Tian J, Ivanovski VN, Abeykoon M, Martin RM, Baranets S, Martin C, Liu Y, Du Q, Wang A, Chen S, Tong X, Zhang W, Bobev S, Koteski VJ, Petrović Č. Absence of long-range magnetic order in Fe1−δ Te2  (δ ≈ 0.1) crystals. in Physical Review B. 2021;104(22):224109.
doi:10.1103/PhysRevB.104.224109 .

Tian, Jianjun, Ivanovski, Valentin N., Abeykoon, Milinda, Martin, Rodica M., Baranets, Sviatoslav, Martin, Catalin, Liu, Yu, Du, Qianheng, Wang, Aifeng, Chen, Shuzhang, Tong, Xiao, Zhang, Weifeng, Bobev, Svilen, Koteski, Vasil J., Petrović, Čedomir, "Absence of long-range magnetic order in Fe1−δ Te2  (δ ≈ 0.1) crystals" in Physical Review B, 104, no. 22 (2021):224109,
https://doi.org/10.1103/PhysRevB.104.224109 . .

TY  - JOUR
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Ivanovski, Valentin N.
AU  - Umićević, Ana
AU  - Toprek, Dragan
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8889
AB  - Substitutionally doped Bi2W1-xMxO6 (M = Mo, Cr, Fe, Zn; x = 0.125, 0,25, 0.5) is investigated using the density functional theory (DFT). For all the investigated transition metal dopants, the optical properties in the visible light range are improved over the undoped Bi2WO6. Irrespective of concentration, the lattice relaxation around the dopants is constrained to the first coordination shell. Mo, Fe, and Cr introduce localized defect states in the band gap, contributing to band gap narrowing. The localized states are hybridized between the impurity d–bands and host W 5d–and O 2p–states. Zn facilitates the reduction of the band gap by inducing a shift of the states near the top of the valence band toward higher energies. Our results suggest that Zn doping on the W lattice site may improve the photocatalytic properties of Bi2WO6 more than the other dopants.
T2  - Applied Surface Science
T1  - Ab initio calculations of the optical and electronic properties of Bi2WO6 doped with Mo, Cr, Fe, and Zn on the W–lattice site
VL  - 515
SP  - 146036
DO  - 10.1016/j.apsusc.2020.146036
ER  - 

@article{
author = "Koteski, Vasil J. and Belošević-Čavor, Jelena and Ivanovski, Valentin N. and Umićević, Ana and Toprek, Dragan",
year = "2020",
abstract = "Substitutionally doped Bi2W1-xMxO6 (M = Mo, Cr, Fe, Zn; x = 0.125, 0,25, 0.5) is investigated using the density functional theory (DFT). For all the investigated transition metal dopants, the optical properties in the visible light range are improved over the undoped Bi2WO6. Irrespective of concentration, the lattice relaxation around the dopants is constrained to the first coordination shell. Mo, Fe, and Cr introduce localized defect states in the band gap, contributing to band gap narrowing. The localized states are hybridized between the impurity d–bands and host W 5d–and O 2p–states. Zn facilitates the reduction of the band gap by inducing a shift of the states near the top of the valence band toward higher energies. Our results suggest that Zn doping on the W lattice site may improve the photocatalytic properties of Bi2WO6 more than the other dopants.",
journal = "Applied Surface Science",
title = "Ab initio calculations of the optical and electronic properties of Bi2WO6 doped with Mo, Cr, Fe, and Zn on the W–lattice site",
volume = "515",
pages = "146036",
doi = "10.1016/j.apsusc.2020.146036"
}

Koteski, V. J., Belošević-Čavor, J., Ivanovski, V. N., Umićević, A.,& Toprek, D.. (2020). Ab initio calculations of the optical and electronic properties of Bi2WO6 doped with Mo, Cr, Fe, and Zn on the W–lattice site. in Applied Surface Science, 515, 146036.
https://doi.org/10.1016/j.apsusc.2020.146036

Koteski VJ, Belošević-Čavor J, Ivanovski VN, Umićević A, Toprek D. Ab initio calculations of the optical and electronic properties of Bi2WO6 doped with Mo, Cr, Fe, and Zn on the W–lattice site. in Applied Surface Science. 2020;515:146036.
doi:10.1016/j.apsusc.2020.146036 .

Koteski, Vasil J., Belošević-Čavor, Jelena, Ivanovski, Valentin N., Umićević, Ana, Toprek, Dragan, "Ab initio calculations of the optical and electronic properties of Bi2WO6 doped with Mo, Cr, Fe, and Zn on the W–lattice site" in Applied Surface Science, 515 (2020):146036,
https://doi.org/10.1016/j.apsusc.2020.146036 . .

TY  - JOUR
AU  - Tian, Jianjun
AU  - Ivanovski, Valentin N.
AU  - Szalda, David
AU  - Lei, Hechang
AU  - Wang, Aifeng
AU  - Liu, Yu
AU  - Zhang, Weifeng
AU  - Koteski, Vasil J.
AU  - Petrović, Čedomir
PY  - 2019
UR  - http://pubs.acs.org/doi/10.1021/acs.inorgchem.8b03089
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8082
AB  - We report the synthesis and characterization of Fe 0.36(4) Pd 0.64(4) Se 2 with a pyrite-type structure. Fe 0.36(4) Pd 0.64(4) Se 2 was synthesized using ambient pressure flux crystal growth methods even though the space group Pa3 is high-pressure polymorph for both FeSe 2 and PdSe 2 . Combined experimental and theoretical analysis reveal magnetic spin glass state below 23 K in 1000 Oe that stems from random Fe/Pd occupancies on the same atomic site. The frozen-in magnetic randomness contributes significantly to electronic transport. Electronic structure calculations confirm dominant d-electron character of hybridized bands and large density of states near the Fermi level. Flux-grown single crystal alloys in Pd-Fe-Se atomic system therefore open new pathway for exploring different polymorphs in crystal structures and their novel properties. © 2019 American Chemical Society.
T2  - Inorganic Chemistry
T1  - Fe0.36(4)Pd 0.64(4)Se 2 : Magnetic Spin-Glass Polymorph of FeSe2 and PdSe2 Stable at Ambient Pressure
VL  - 58
IS  - 5
SP  - 3107
EP  - 3114
DO  - 10.1021/acs.inorgchem.8b03089
ER  - 

@article{
author = "Tian, Jianjun and Ivanovski, Valentin N. and Szalda, David and Lei, Hechang and Wang, Aifeng and Liu, Yu and Zhang, Weifeng and Koteski, Vasil J. and Petrović, Čedomir",
year = "2019",
abstract = "We report the synthesis and characterization of Fe 0.36(4) Pd 0.64(4) Se 2 with a pyrite-type structure. Fe 0.36(4) Pd 0.64(4) Se 2 was synthesized using ambient pressure flux crystal growth methods even though the space group Pa3 is high-pressure polymorph for both FeSe 2 and PdSe 2 . Combined experimental and theoretical analysis reveal magnetic spin glass state below 23 K in 1000 Oe that stems from random Fe/Pd occupancies on the same atomic site. The frozen-in magnetic randomness contributes significantly to electronic transport. Electronic structure calculations confirm dominant d-electron character of hybridized bands and large density of states near the Fermi level. Flux-grown single crystal alloys in Pd-Fe-Se atomic system therefore open new pathway for exploring different polymorphs in crystal structures and their novel properties. © 2019 American Chemical Society.",
journal = "Inorganic Chemistry",
title = "Fe0.36(4)Pd 0.64(4)Se 2 : Magnetic Spin-Glass Polymorph of FeSe2 and PdSe2 Stable at Ambient Pressure",
volume = "58",
number = "5",
pages = "3107-3114",
doi = "10.1021/acs.inorgchem.8b03089"
}

Tian, J., Ivanovski, V. N., Szalda, D., Lei, H., Wang, A., Liu, Y., Zhang, W., Koteski, V. J.,& Petrović, Č.. (2019). Fe0.36(4)Pd 0.64(4)Se 2 : Magnetic Spin-Glass Polymorph of FeSe2 and PdSe2 Stable at Ambient Pressure. in Inorganic Chemistry, 58(5), 3107-3114.
https://doi.org/10.1021/acs.inorgchem.8b03089

Tian J, Ivanovski VN, Szalda D, Lei H, Wang A, Liu Y, Zhang W, Koteski VJ, Petrović Č. Fe0.36(4)Pd 0.64(4)Se 2 : Magnetic Spin-Glass Polymorph of FeSe2 and PdSe2 Stable at Ambient Pressure. in Inorganic Chemistry. 2019;58(5):3107-3114.
doi:10.1021/acs.inorgchem.8b03089 .

Tian, Jianjun, Ivanovski, Valentin N., Szalda, David, Lei, Hechang, Wang, Aifeng, Liu, Yu, Zhang, Weifeng, Koteski, Vasil J., Petrović, Čedomir, "Fe0.36(4)Pd 0.64(4)Se 2 : Magnetic Spin-Glass Polymorph of FeSe2 and PdSe2 Stable at Ambient Pressure" in Inorganic Chemistry, 58, no. 5 (2019):3107-3114,
https://doi.org/10.1021/acs.inorgchem.8b03089 . .

TY  - JOUR
AU  - Ivanovski, Valentin N.
AU  - Belošević-Čavor, Jelena
AU  - Rajić, Vladimir
AU  - Umićević, Ana
AU  - Marković, Smilja
AU  - Kusigerski, Vladan
AU  - Mitrić, Miodrag
AU  - Koteski, Vasil J.
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8515
AB  - In order to study the effect of Fe cation substitution on the local structure, defect formation, and hyperfine interactions in ZnO, Mössbauer spectroscopy measurements of the microwave processed Zn 1 - x Fe x O (x = 0.05, 0.10, 0.15, and 0.20) nanoparticles, together with ab initio calculations, were performed. Complementary information on the distribution of particle size and morphology, as well as magnetic properties, were obtained by X-ray diffraction, transmission electron microscopy, and squid-magnetometry. The selected model for analyzing the Mössbauer spectra of our samples is a distribution of quadrupole splittings. The fitting model with two Lorentz doublets was rejected due to its failure to include larger doublets. The Fe 3 + ions do not yield magnetic ordering in the samples at room temperature. The results from first-principles calculations confirm that the major component of the Mössbauer spectra corresponds to the Fe-alloyed ZnO with Zn vacancy in the next nearest neighbor environment. The magnetic measurements are consistent with the description of the distribution of iron ions over the randomly formed clusters in the ZnO host lattice. While at room temperature all the samples are paramagnetic, magnetic interactions cause a transition into a cluster spin-glass state at low temperatures. © 2019 Author(s).
T2  - Journal of Applied Physics
T1  - A study of defect structures in Fe-alloyed ZnO: Morphology, magnetism, and hyperfine interactions
VL  - 126
IS  - 12
SP  - 125703
DO  - 10.1063/1.5095837
ER  - 

@article{
author = "Ivanovski, Valentin N. and Belošević-Čavor, Jelena and Rajić, Vladimir and Umićević, Ana and Marković, Smilja and Kusigerski, Vladan and Mitrić, Miodrag and Koteski, Vasil J.",
year = "2019",
abstract = "In order to study the effect of Fe cation substitution on the local structure, defect formation, and hyperfine interactions in ZnO, Mössbauer spectroscopy measurements of the microwave processed Zn 1 - x Fe x O (x = 0.05, 0.10, 0.15, and 0.20) nanoparticles, together with ab initio calculations, were performed. Complementary information on the distribution of particle size and morphology, as well as magnetic properties, were obtained by X-ray diffraction, transmission electron microscopy, and squid-magnetometry. The selected model for analyzing the Mössbauer spectra of our samples is a distribution of quadrupole splittings. The fitting model with two Lorentz doublets was rejected due to its failure to include larger doublets. The Fe 3 + ions do not yield magnetic ordering in the samples at room temperature. The results from first-principles calculations confirm that the major component of the Mössbauer spectra corresponds to the Fe-alloyed ZnO with Zn vacancy in the next nearest neighbor environment. The magnetic measurements are consistent with the description of the distribution of iron ions over the randomly formed clusters in the ZnO host lattice. While at room temperature all the samples are paramagnetic, magnetic interactions cause a transition into a cluster spin-glass state at low temperatures. © 2019 Author(s).",
journal = "Journal of Applied Physics",
title = "A study of defect structures in Fe-alloyed ZnO: Morphology, magnetism, and hyperfine interactions",
volume = "126",
number = "12",
pages = "125703",
doi = "10.1063/1.5095837"
}

Ivanovski, V. N., Belošević-Čavor, J., Rajić, V., Umićević, A., Marković, S., Kusigerski, V., Mitrić, M.,& Koteski, V. J.. (2019). A study of defect structures in Fe-alloyed ZnO: Morphology, magnetism, and hyperfine interactions. in Journal of Applied Physics, 126(12), 125703.
https://doi.org/10.1063/1.5095837

Ivanovski VN, Belošević-Čavor J, Rajić V, Umićević A, Marković S, Kusigerski V, Mitrić M, Koteski VJ. A study of defect structures in Fe-alloyed ZnO: Morphology, magnetism, and hyperfine interactions. in Journal of Applied Physics. 2019;126(12):125703.
doi:10.1063/1.5095837 .

Ivanovski, Valentin N., Belošević-Čavor, Jelena, Rajić, Vladimir, Umićević, Ana, Marković, Smilja, Kusigerski, Vladan, Mitrić, Miodrag, Koteski, Vasil J., "A study of defect structures in Fe-alloyed ZnO: Morphology, magnetism, and hyperfine interactions" in Journal of Applied Physics, 126, no. 12 (2019):125703,
https://doi.org/10.1063/1.5095837 . .

TY  - JOUR
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Umićević, Ana
AU  - Ivanovski, Valentin N.
PY  - 2018
UR  - http://linkinghub.elsevier.com/retrieve/pii/S0927025618303306
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7700
AB  - Density functional theory (DFT) calculations were performed to address the effects of 5d transition metals (TM) doping on the electronic structure properties of rutile TiO2, using both the modified Becke-Johnson (mBJ) and on-site hybrid functional. The calculations show that there is a reduction of band gap in almost all the investigated cases, except when TiO2is doped with Ta. Some of the investigated systems (Re, W, Os, Ir) exhibit pronounced spin polarization, mainly arising from the TM atoms. In addition, a large increase of band gap is observed, when switching from a 24-atoms to 48-atoms supercell, while further enlarging the supercell size doesn't affect the band gap significantly. Among the investigated transition metals, Pt and Ir are the best candidates for improving the photocatalytic properties of rutile TiO2through substitutional doping.
T2  - Computational Materials Science
T1  - Effect of 5d transition metals doping on the photocatalytic properties of rutile TiO 2
VL  - 151
SP  - 328
EP  - 337
DO  - 10.1016/j.commatsci.2018.05.022
ER  - 

@article{
author = "Belošević-Čavor, Jelena and Koteski, Vasil J. and Umićević, Ana and Ivanovski, Valentin N.",
year = "2018",
abstract = "Density functional theory (DFT) calculations were performed to address the effects of 5d transition metals (TM) doping on the electronic structure properties of rutile TiO2, using both the modified Becke-Johnson (mBJ) and on-site hybrid functional. The calculations show that there is a reduction of band gap in almost all the investigated cases, except when TiO2is doped with Ta. Some of the investigated systems (Re, W, Os, Ir) exhibit pronounced spin polarization, mainly arising from the TM atoms. In addition, a large increase of band gap is observed, when switching from a 24-atoms to 48-atoms supercell, while further enlarging the supercell size doesn't affect the band gap significantly. Among the investigated transition metals, Pt and Ir are the best candidates for improving the photocatalytic properties of rutile TiO2through substitutional doping.",
journal = "Computational Materials Science",
title = "Effect of 5d transition metals doping on the photocatalytic properties of rutile TiO 2",
volume = "151",
pages = "328-337",
doi = "10.1016/j.commatsci.2018.05.022"
}

Belošević-Čavor, J., Koteski, V. J., Umićević, A.,& Ivanovski, V. N.. (2018). Effect of 5d transition metals doping on the photocatalytic properties of rutile TiO 2. in Computational Materials Science, 151, 328-337.
https://doi.org/10.1016/j.commatsci.2018.05.022

Belošević-Čavor J, Koteski VJ, Umićević A, Ivanovski VN. Effect of 5d transition metals doping on the photocatalytic properties of rutile TiO 2. in Computational Materials Science. 2018;151:328-337.
doi:10.1016/j.commatsci.2018.05.022 .

Belošević-Čavor, Jelena, Koteski, Vasil J., Umićević, Ana, Ivanovski, Valentin N., "Effect of 5d transition metals doping on the photocatalytic properties of rutile TiO 2" in Computational Materials Science, 151 (2018):328-337,
https://doi.org/10.1016/j.commatsci.2018.05.022 . .

TY  - JOUR
AU  - Toprek, Dragan
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Ivanovski, Valentin N.
AU  - Umićević, Ana
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1834
AB  - In this paper we investigated the effects of Fe-doping of the anatase TiO2 (1 0 1) surface on the crystal structure, electronic and optical properties, and impurity formation energy by means of density functional theory (DFT). The calculations were performed by the SIESTA DFT code and were carried out by using Troullier-Martins pseudopotentials for the 12-electron valence configuration (3s(2)3p(6)3d(2)4s(2)) of Ti atom, 6-electron valence configuration (2s(2)p(4)) of O atom and 8-electron valence configuration (3d(6)4s(2)) of Fe atom. We used a double- zeta basis set including polarization functions. All calculations were spin-polarized. The mechanism of narrowing the band gap and increasing the photocatalytic activity in the visible light region, of the doped TiO2 is discussed by investigating the density of state. The band gap decreases as the concentration of the dopant increases. The Partial Density of States (PDOS) is not the same in the case of spin-up state or spin-down state. Enhanced optical absorption, for light polarized in the z direction (parallel to the surface normal) is clearly observed for Fe doped as compared to the pure anatase TiO2 and the optical absorption is found to increase with the increase in the Fe concentration. The DFT results indicate that the source of the increasing photocatalytic activity in the visible light region of the Fe doped material is due to the introduction of additional electronic states within the band gap. Since the Fe atoms are more stable in Ti substitutional lattice positions for the entire range of Fermi energy E-F over the band gap, only this substitutional position is considered. We hope that our results will highlight a route to improved electronic and optical properties of anatase TiO2 for industrial applications. (C) 2017 Elsevier B.V. All rights reserved.
T2  - Computational and Theoretical Chemistry
T1  - Ab initio study of electronic and optical properties of Fe doped anatase TiO2 (101) surface
VL  - 1120
SP  - 17
EP  - 23
DO  - 10.1016/j.comptc.2017.09.024
ER  - 

@article{
author = "Toprek, Dragan and Koteski, Vasil J. and Belošević-Čavor, Jelena and Ivanovski, Valentin N. and Umićević, Ana",
year = "2017",
abstract = "In this paper we investigated the effects of Fe-doping of the anatase TiO2 (1 0 1) surface on the crystal structure, electronic and optical properties, and impurity formation energy by means of density functional theory (DFT). The calculations were performed by the SIESTA DFT code and were carried out by using Troullier-Martins pseudopotentials for the 12-electron valence configuration (3s(2)3p(6)3d(2)4s(2)) of Ti atom, 6-electron valence configuration (2s(2)p(4)) of O atom and 8-electron valence configuration (3d(6)4s(2)) of Fe atom. We used a double- zeta basis set including polarization functions. All calculations were spin-polarized. The mechanism of narrowing the band gap and increasing the photocatalytic activity in the visible light region, of the doped TiO2 is discussed by investigating the density of state. The band gap decreases as the concentration of the dopant increases. The Partial Density of States (PDOS) is not the same in the case of spin-up state or spin-down state. Enhanced optical absorption, for light polarized in the z direction (parallel to the surface normal) is clearly observed for Fe doped as compared to the pure anatase TiO2 and the optical absorption is found to increase with the increase in the Fe concentration. The DFT results indicate that the source of the increasing photocatalytic activity in the visible light region of the Fe doped material is due to the introduction of additional electronic states within the band gap. Since the Fe atoms are more stable in Ti substitutional lattice positions for the entire range of Fermi energy E-F over the band gap, only this substitutional position is considered. We hope that our results will highlight a route to improved electronic and optical properties of anatase TiO2 for industrial applications. (C) 2017 Elsevier B.V. All rights reserved.",
journal = "Computational and Theoretical Chemistry",
title = "Ab initio study of electronic and optical properties of Fe doped anatase TiO2 (101) surface",
volume = "1120",
pages = "17-23",
doi = "10.1016/j.comptc.2017.09.024"
}

Toprek, D., Koteski, V. J., Belošević-Čavor, J., Ivanovski, V. N.,& Umićević, A.. (2017). Ab initio study of electronic and optical properties of Fe doped anatase TiO2 (101) surface. in Computational and Theoretical Chemistry, 1120, 17-23.
https://doi.org/10.1016/j.comptc.2017.09.024

Toprek D, Koteski VJ, Belošević-Čavor J, Ivanovski VN, Umićević A. Ab initio study of electronic and optical properties of Fe doped anatase TiO2 (101) surface. in Computational and Theoretical Chemistry. 2017;1120:17-23.
doi:10.1016/j.comptc.2017.09.024 .

Toprek, Dragan, Koteski, Vasil J., Belošević-Čavor, Jelena, Ivanovski, Valentin N., Umićević, Ana, "Ab initio study of electronic and optical properties of Fe doped anatase TiO2 (101) surface" in Computational and Theoretical Chemistry, 1120 (2017):17-23,
https://doi.org/10.1016/j.comptc.2017.09.024 . .

TY  - JOUR
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Umićević, Ana
AU  - Ivanovski, Valentin N.
AU  - Toprek, Dragan
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1721
AB  - Substitutionally and interstitially Cu/Nco-doped anatase TiO2(101) surface is investigated by using density functional theory (DFT) calculations. The results suggest improved visible light photocatalytic activity over undoped anatase TiO2. Sizable lattice relaxation around the dopants is observed, followed by a formation of N-O bond. Depending on the local arrangement of atoms, localized states above the valence band maximum, deep into the band gap, and below the conduction band minimum are found. In addition, our calculation also predict band gap narrowing. The hybridization of the Cu 3d and N 2p states within the band gap and the other electronic and optical properties suggest a synergistic effect of the dopants in the enhancement of the visible light absorption on the (101) anatase surface. (C) 2017 Elsevier B.V. All rights reserved.
T2  - Applied Surface Science
T1  - Improving the photocatalytic properties of anatase TiO2(101) surface by co-doping with Cu and N: Ab initio study
VL  - 425
SP  - 1095
EP  - 1100
DO  - 10.1016/j.apsusc.2017.07.064
ER  - 

@article{
author = "Koteski, Vasil J. and Belošević-Čavor, Jelena and Umićević, Ana and Ivanovski, Valentin N. and Toprek, Dragan",
year = "2017",
abstract = "Substitutionally and interstitially Cu/Nco-doped anatase TiO2(101) surface is investigated by using density functional theory (DFT) calculations. The results suggest improved visible light photocatalytic activity over undoped anatase TiO2. Sizable lattice relaxation around the dopants is observed, followed by a formation of N-O bond. Depending on the local arrangement of atoms, localized states above the valence band maximum, deep into the band gap, and below the conduction band minimum are found. In addition, our calculation also predict band gap narrowing. The hybridization of the Cu 3d and N 2p states within the band gap and the other electronic and optical properties suggest a synergistic effect of the dopants in the enhancement of the visible light absorption on the (101) anatase surface. (C) 2017 Elsevier B.V. All rights reserved.",
journal = "Applied Surface Science",
title = "Improving the photocatalytic properties of anatase TiO2(101) surface by co-doping with Cu and N: Ab initio study",
volume = "425",
pages = "1095-1100",
doi = "10.1016/j.apsusc.2017.07.064"
}

Koteski, V. J., Belošević-Čavor, J., Umićević, A., Ivanovski, V. N.,& Toprek, D.. (2017). Improving the photocatalytic properties of anatase TiO2(101) surface by co-doping with Cu and N: Ab initio study. in Applied Surface Science, 425, 1095-1100.
https://doi.org/10.1016/j.apsusc.2017.07.064

Koteski VJ, Belošević-Čavor J, Umićević A, Ivanovski VN, Toprek D. Improving the photocatalytic properties of anatase TiO2(101) surface by co-doping with Cu and N: Ab initio study. in Applied Surface Science. 2017;425:1095-1100.
doi:10.1016/j.apsusc.2017.07.064 .

Koteski, Vasil J., Belošević-Čavor, Jelena, Umićević, Ana, Ivanovski, Valentin N., Toprek, Dragan, "Improving the photocatalytic properties of anatase TiO2(101) surface by co-doping with Cu and N: Ab initio study" in Applied Surface Science, 425 (2017):1095-1100,
https://doi.org/10.1016/j.apsusc.2017.07.064 . .

TY  - JOUR
AU  - Koteski, Vasil J.
AU  - Ivanovski, Valentin N.
AU  - Umićević, Ana
AU  - Belošević-Čavor, Jelena
AU  - Toprek, Dragan
AU  - Mahnke, Heinz-Eberhard
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1688
AB  - Magnetic ground states, local crystallographic environment of Fe, and hyperfine interaction parameters in tetragonal FeX (X = S, Se, Te) are investigated by means of density functional theory (DFT) calculations using augmented plane waves plus local orbitals (APW + lo) method. We use several different magnetic configurations to evaluate the magnetic and electronic properties of this system, as well as the hyperfine interaction parameters at Fe lattice site. The results obtained for the ground state collinear anti-ferromagnetic arrangement relatively well reproduce the quadrupole splitting and isomer shifts from the available Mossbauer measurements. The Baders atoms in molecule charge density analysis indicates bonding of closed-shell type and a sizable charge transfer from Fe to X. The system properties are sensitive to the structural optimization of the position of the chalcogen atom with respect to the iron plane. (C) 2017 Elsevier B.V. All rights reserved.
T2  - Journal of Magnetism and Magnetic Materials
T1  - First-principles calculations of tetragonal FeX (X = S, Se, Te): Magnetism, hyperfine-interaction, and bonding
VL  - 441
SP  - 769
EP  - 775
DO  - 10.1016/j.jmmm.2017.06.092
ER  - 

@article{
author = "Koteski, Vasil J. and Ivanovski, Valentin N. and Umićević, Ana and Belošević-Čavor, Jelena and Toprek, Dragan and Mahnke, Heinz-Eberhard",
year = "2017",
abstract = "Magnetic ground states, local crystallographic environment of Fe, and hyperfine interaction parameters in tetragonal FeX (X = S, Se, Te) are investigated by means of density functional theory (DFT) calculations using augmented plane waves plus local orbitals (APW + lo) method. We use several different magnetic configurations to evaluate the magnetic and electronic properties of this system, as well as the hyperfine interaction parameters at Fe lattice site. The results obtained for the ground state collinear anti-ferromagnetic arrangement relatively well reproduce the quadrupole splitting and isomer shifts from the available Mossbauer measurements. The Baders atoms in molecule charge density analysis indicates bonding of closed-shell type and a sizable charge transfer from Fe to X. The system properties are sensitive to the structural optimization of the position of the chalcogen atom with respect to the iron plane. (C) 2017 Elsevier B.V. All rights reserved.",
journal = "Journal of Magnetism and Magnetic Materials",
title = "First-principles calculations of tetragonal FeX (X = S, Se, Te): Magnetism, hyperfine-interaction, and bonding",
volume = "441",
pages = "769-775",
doi = "10.1016/j.jmmm.2017.06.092"
}

Koteski, V. J., Ivanovski, V. N., Umićević, A., Belošević-Čavor, J., Toprek, D.,& Mahnke, H.. (2017). First-principles calculations of tetragonal FeX (X = S, Se, Te): Magnetism, hyperfine-interaction, and bonding. in Journal of Magnetism and Magnetic Materials, 441, 769-775.
https://doi.org/10.1016/j.jmmm.2017.06.092

Koteski VJ, Ivanovski VN, Umićević A, Belošević-Čavor J, Toprek D, Mahnke H. First-principles calculations of tetragonal FeX (X = S, Se, Te): Magnetism, hyperfine-interaction, and bonding. in Journal of Magnetism and Magnetic Materials. 2017;441:769-775.
doi:10.1016/j.jmmm.2017.06.092 .

Koteski, Vasil J., Ivanovski, Valentin N., Umićević, Ana, Belošević-Čavor, Jelena, Toprek, Dragan, Mahnke, Heinz-Eberhard, "First-principles calculations of tetragonal FeX (X = S, Se, Te): Magnetism, hyperfine-interaction, and bonding" in Journal of Magnetism and Magnetic Materials, 441 (2017):769-775,
https://doi.org/10.1016/j.jmmm.2017.06.092 . .

TY  - JOUR
AU  - Umićević, Ana
AU  - Mahnke, Heinz-Eberhard
AU  - Belošević-Čavor, Jelena
AU  - Cekić, Božidar Đ.
AU  - Schumacher, Gerhard
AU  - Mađarević, Ivan
AU  - Koteski, Vasil J.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7091
AB  - X-ray absorption spectroscopy is employed to investigate site preference and lattice relaxation around Mo, Ru, Hf, W and Re dopants in Ni3Al. The site occupation preference and the measured distances between the refractory elements as dopants and the nearest host atoms are compared with the results of ab initio calculations within the density functional theory. Combined experimental and theoretical results indicate that Mo, Hf, W and Re atoms reside on the Al sublattice in Ni3Al, while Ru atoms occupy the Ni sublattice. A more pronounced lattice relaxation was detected in the case of Hf and Ru doping, with a strong outward relaxation of the nearest Ni and Al atoms.
T2  - Journal of Synchrotron Radiation
T1  - Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al
VL  - 23
SP  - 286
EP  - 292
DO  - 10.1107/S1600577515020688
ER  - 

@article{
author = "Umićević, Ana and Mahnke, Heinz-Eberhard and Belošević-Čavor, Jelena and Cekić, Božidar Đ. and Schumacher, Gerhard and Mađarević, Ivan and Koteski, Vasil J.",
year = "2016",
abstract = "X-ray absorption spectroscopy is employed to investigate site preference and lattice relaxation around Mo, Ru, Hf, W and Re dopants in Ni3Al. The site occupation preference and the measured distances between the refractory elements as dopants and the nearest host atoms are compared with the results of ab initio calculations within the density functional theory. Combined experimental and theoretical results indicate that Mo, Hf, W and Re atoms reside on the Al sublattice in Ni3Al, while Ru atoms occupy the Ni sublattice. A more pronounced lattice relaxation was detected in the case of Hf and Ru doping, with a strong outward relaxation of the nearest Ni and Al atoms.",
journal = "Journal of Synchrotron Radiation",
title = "Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al",
volume = "23",
pages = "286-292",
doi = "10.1107/S1600577515020688"
}

Umićević, A., Mahnke, H., Belošević-Čavor, J., Cekić, B. Đ., Schumacher, G., Mađarević, I.,& Koteski, V. J.. (2016). Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al. in Journal of Synchrotron Radiation, 23, 286-292.
https://doi.org/10.1107/S1600577515020688

Umićević A, Mahnke H, Belošević-Čavor J, Cekić BĐ, Schumacher G, Mađarević I, Koteski VJ. Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al. in Journal of Synchrotron Radiation. 2016;23:286-292.
doi:10.1107/S1600577515020688 .

Umićević, Ana, Mahnke, Heinz-Eberhard, Belošević-Čavor, Jelena, Cekić, Božidar Đ., Schumacher, Gerhard, Mađarević, Ivan, Koteski, Vasil J., "Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al" in Journal of Synchrotron Radiation, 23 (2016):286-292,
https://doi.org/10.1107/S1600577515020688 . .

TY  - JOUR
AU  - Toprek, Dragan
AU  - Koteski, Vasil J.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/981
AB  - The stability and structure of titanium doped gold clusters (AunTi; n = 1-32) are studied by density functional theory calculations, as implemented in the first principles code SIESTA. The exchange and correlation effects were calculated within the generalized gradient approximation (GGA) parametrized by Perdew, Burke and Ernzerhof (PBE). We used norm conserving Troullier-Martins pseudopotentials for the 10-electron valence configuration of Ti and 11-electron valence configuration of Au. All calculations were spin-polarized. The global energy minimum geometries of the clusters were searched for by using the simulated annealing technique. The stability of the clusters is discussed on the basis of the binding energy per atom, second-order energy difference, vertical ionization potential, vertical electron affinities, HOMO-LUMO energy gap and vibrational frequencies. Based on the simultaneous criteria of high binding energy, high band gap, high vertical ionization potential, and low electron affinity, it is found that Au4Ti and Au14Ti clusters have a higher stability and are candidates for magic clusters, which confirms the already known results from previous works. The new result presented in this paper is that the Au20Ti and Au30Ti clusters have a higher stability too. In general, the clusters with even n are more stable than the clusters with odd n. Most of the clusters with even n are non-magnetic (total magnetic moment is zero). Our results also suggest that only the Au3Ti, Au7Ti and Au8Ti clusters have a planar structure. (C) 2016 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Computational and Theoretical Chemistry
T1  - Ab initio calculations of the structure, energetics and stability of AunTi (n=1-32) clusters
VL  - 1081
SP  - 9
EP  - 17
DO  - 10.1016/j.comptc.2016.02.005
ER  - 

@article{
author = "Toprek, Dragan and Koteski, Vasil J.",
year = "2016",
abstract = "The stability and structure of titanium doped gold clusters (AunTi; n = 1-32) are studied by density functional theory calculations, as implemented in the first principles code SIESTA. The exchange and correlation effects were calculated within the generalized gradient approximation (GGA) parametrized by Perdew, Burke and Ernzerhof (PBE). We used norm conserving Troullier-Martins pseudopotentials for the 10-electron valence configuration of Ti and 11-electron valence configuration of Au. All calculations were spin-polarized. The global energy minimum geometries of the clusters were searched for by using the simulated annealing technique. The stability of the clusters is discussed on the basis of the binding energy per atom, second-order energy difference, vertical ionization potential, vertical electron affinities, HOMO-LUMO energy gap and vibrational frequencies. Based on the simultaneous criteria of high binding energy, high band gap, high vertical ionization potential, and low electron affinity, it is found that Au4Ti and Au14Ti clusters have a higher stability and are candidates for magic clusters, which confirms the already known results from previous works. The new result presented in this paper is that the Au20Ti and Au30Ti clusters have a higher stability too. In general, the clusters with even n are more stable than the clusters with odd n. Most of the clusters with even n are non-magnetic (total magnetic moment is zero). Our results also suggest that only the Au3Ti, Au7Ti and Au8Ti clusters have a planar structure. (C) 2016 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Computational and Theoretical Chemistry",
title = "Ab initio calculations of the structure, energetics and stability of AunTi (n=1-32) clusters",
volume = "1081",
pages = "9-17",
doi = "10.1016/j.comptc.2016.02.005"
}

Toprek, D.,& Koteski, V. J.. (2016). Ab initio calculations of the structure, energetics and stability of AunTi (n=1-32) clusters. in Computational and Theoretical Chemistry
Elsevier., 1081, 9-17.
https://doi.org/10.1016/j.comptc.2016.02.005

Toprek D, Koteski VJ. Ab initio calculations of the structure, energetics and stability of AunTi (n=1-32) clusters. in Computational and Theoretical Chemistry. 2016;1081:9-17.
doi:10.1016/j.comptc.2016.02.005 .

Toprek, Dragan, Koteski, Vasil J., "Ab initio calculations of the structure, energetics and stability of AunTi (n=1-32) clusters" in Computational and Theoretical Chemistry, 1081 (2016):9-17,
https://doi.org/10.1016/j.comptc.2016.02.005 . .

TY  - JOUR
AU  - Ivanovski, Valentin N.
AU  - Cekić, Božidar Đ.
AU  - Umićević, Ana
AU  - Barudžija, Tanja
AU  - Schumacher, G.
AU  - Mađarević, Ivan
AU  - Koteski, Vasil J.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/249
AB  - Perturbed angular correlation measurements of the hyperfine interactions of the Ta-181 probe in the polycrystalline intermetallic Ni3Al doped with 0.5 and 5 at.% Hf were performed in the temperature range 78-1230 K. The observed local hyperfine fields at the Hf-181/Ta-181 probe showed that Hf atoms are substituting on Al sites in the L1(2) structure of Ni3Al. The two minor electric quadrupole interactions that were found for each Ni3Al alloy are discussed taking into account the L1(2) cubic structure and its two tetragonal distortions: D0(22) and L6(0). The presence of two tetragonal transformations of the parent cubic L1(2) lattice in 0.5 at.% Hf and 5 at.% Hf doped Ni3Al was revealed by X-ray diffraction. The ab initio calculations, performed with the projector augmented wave method correctly reproduce the experimental results and enable discussion on the structural and electronic properties of the polycrystalline alloys. The experimental and theoretical investigations showed that hafnium additions prefer aluminum sites in Ni3Al. (C) 2014 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study
VL  - 622
SP  - 541
EP  - 547
DO  - 10.1016/j.jallcom.2014.10.132
ER  - 

@article{
author = "Ivanovski, Valentin N. and Cekić, Božidar Đ. and Umićević, Ana and Barudžija, Tanja and Schumacher, G. and Mađarević, Ivan and Koteski, Vasil J.",
year = "2015",
abstract = "Perturbed angular correlation measurements of the hyperfine interactions of the Ta-181 probe in the polycrystalline intermetallic Ni3Al doped with 0.5 and 5 at.% Hf were performed in the temperature range 78-1230 K. The observed local hyperfine fields at the Hf-181/Ta-181 probe showed that Hf atoms are substituting on Al sites in the L1(2) structure of Ni3Al. The two minor electric quadrupole interactions that were found for each Ni3Al alloy are discussed taking into account the L1(2) cubic structure and its two tetragonal distortions: D0(22) and L6(0). The presence of two tetragonal transformations of the parent cubic L1(2) lattice in 0.5 at.% Hf and 5 at.% Hf doped Ni3Al was revealed by X-ray diffraction. The ab initio calculations, performed with the projector augmented wave method correctly reproduce the experimental results and enable discussion on the structural and electronic properties of the polycrystalline alloys. The experimental and theoretical investigations showed that hafnium additions prefer aluminum sites in Ni3Al. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study",
volume = "622",
pages = "541-547",
doi = "10.1016/j.jallcom.2014.10.132"
}

Ivanovski, V. N., Cekić, B. Đ., Umićević, A., Barudžija, T., Schumacher, G., Mađarević, I.,& Koteski, V. J.. (2015). Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study. in Journal of Alloys and Compounds, 622, 541-547.
https://doi.org/10.1016/j.jallcom.2014.10.132

Ivanovski VN, Cekić BĐ, Umićević A, Barudžija T, Schumacher G, Mađarević I, Koteski VJ. Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study. in Journal of Alloys and Compounds. 2015;622:541-547.
doi:10.1016/j.jallcom.2014.10.132 .

Ivanovski, Valentin N., Cekić, Božidar Đ., Umićević, Ana, Barudžija, Tanja, Schumacher, G., Mađarević, Ivan, Koteski, Vasil J., "Site preference of Hf dopant in Ni3Al alloys: A perturbed angular correlation study" in Journal of Alloys and Compounds, 622 (2015):541-547,
https://doi.org/10.1016/j.jallcom.2014.10.132 . .

TY  - JOUR
AU  - Ivanovski, Valentin N.
AU  - Umićević, Ana
AU  - Belošević-Čavor, Jelena
AU  - Lei, Hechang
AU  - Li, Lijun
AU  - Cekić, Božidar Đ.
AU  - Koteski, Vasil J.
AU  - Petrović, Čedomir
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/749
AB  - The local electronic and magnetic structure, hyperfine interactions, and phase composition of polycrystalline Ni-deficient Ni3-xFexAl (x = 0.18 and 0.36) were investigated by means of Fe-57 Mossbauer spectroscopy. The samples were characterized by X-ray diffraction and magnetization measurements. The ab initio calculations performed with the projector augmented wave method and the calculations of the energies of iron point defects were done to elucidate the electronic structure and site preference of Fe doped Ni3Al. The value of calculated electric field gradient tensor V-zz = 1.6 10(21) Vm(-2) matches well with the results of Mossbauer spectroscopy and indicates that the Fe atoms occupy Ni sites. (C) 2015 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Local structure study of Fe dopants in Ni-deficit Ni3Al alloys
VL  - 651
SP  - 705
EP  - 711
DO  - 10.1016/j.jallcom.2015.08.171
ER  - 

@article{
author = "Ivanovski, Valentin N. and Umićević, Ana and Belošević-Čavor, Jelena and Lei, Hechang and Li, Lijun and Cekić, Božidar Đ. and Koteski, Vasil J. and Petrović, Čedomir",
year = "2015",
abstract = "The local electronic and magnetic structure, hyperfine interactions, and phase composition of polycrystalline Ni-deficient Ni3-xFexAl (x = 0.18 and 0.36) were investigated by means of Fe-57 Mossbauer spectroscopy. The samples were characterized by X-ray diffraction and magnetization measurements. The ab initio calculations performed with the projector augmented wave method and the calculations of the energies of iron point defects were done to elucidate the electronic structure and site preference of Fe doped Ni3Al. The value of calculated electric field gradient tensor V-zz = 1.6 10(21) Vm(-2) matches well with the results of Mossbauer spectroscopy and indicates that the Fe atoms occupy Ni sites. (C) 2015 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Local structure study of Fe dopants in Ni-deficit Ni3Al alloys",
volume = "651",
pages = "705-711",
doi = "10.1016/j.jallcom.2015.08.171"
}

Ivanovski, V. N., Umićević, A., Belošević-Čavor, J., Lei, H., Li, L., Cekić, B. Đ., Koteski, V. J.,& Petrović, Č.. (2015). Local structure study of Fe dopants in Ni-deficit Ni3Al alloys. in Journal of Alloys and Compounds, 651, 705-711.
https://doi.org/10.1016/j.jallcom.2015.08.171

Ivanovski VN, Umićević A, Belošević-Čavor J, Lei H, Li L, Cekić BĐ, Koteski VJ, Petrović Č. Local structure study of Fe dopants in Ni-deficit Ni3Al alloys. in Journal of Alloys and Compounds. 2015;651:705-711.
doi:10.1016/j.jallcom.2015.08.171 .

Ivanovski, Valentin N., Umićević, Ana, Belošević-Čavor, Jelena, Lei, Hechang, Li, Lijun, Cekić, Božidar Đ., Koteski, Vasil J., Petrović, Čedomir, "Local structure study of Fe dopants in Ni-deficit Ni3Al alloys" in Journal of Alloys and Compounds, 651 (2015):705-711,
https://doi.org/10.1016/j.jallcom.2015.08.171 . .

TY  - JOUR
AU  - Belošević-Čavor, Jelena
AU  - Batalović, Katarina
AU  - Koteski, Vasil J.
AU  - Radaković, Jana
AU  - Rangel, Carmen Mireya
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/676
AB  - Substitutional N to O and M to Ti (M = Pt, V, Sb) codoped rutile TiO2 was investigated using density functional theory (OFT) based calculations with both standard and hybrid exchange-correlation functionals. The band gaps calculated using generalized gradient approximation (GGA) exhibited narrowing compared to the pure rutile TiO2 in all the investigated cases. In contrast, the results obtained with hybrid exchange-correlation functional showed that there was no band gap narrowing, but doping induced localized states within the band gap just above the valence band, as well as below the conduction band for Pt doped TiO2. The presence of broad intermediate states (IS) in the band gap could enhance visible light absorption through a two step optical transition from the valence to the conduction band via the IS and at the same time lower recombination of the photo-generated charges. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
T2  - International Journal of Hydrogen Energy
T1  - Enhancing photocatalytic properties of rutile TiO2 by codoping with N and metals - Ab initio study
VL  - 40
IS  - 31
SP  - 9696
EP  - 9703
DO  - 10.1016/j.ijhydene.2015.06.001
ER  - 

@article{
author = "Belošević-Čavor, Jelena and Batalović, Katarina and Koteski, Vasil J. and Radaković, Jana and Rangel, Carmen Mireya",
year = "2015",
abstract = "Substitutional N to O and M to Ti (M = Pt, V, Sb) codoped rutile TiO2 was investigated using density functional theory (OFT) based calculations with both standard and hybrid exchange-correlation functionals. The band gaps calculated using generalized gradient approximation (GGA) exhibited narrowing compared to the pure rutile TiO2 in all the investigated cases. In contrast, the results obtained with hybrid exchange-correlation functional showed that there was no band gap narrowing, but doping induced localized states within the band gap just above the valence band, as well as below the conduction band for Pt doped TiO2. The presence of broad intermediate states (IS) in the band gap could enhance visible light absorption through a two step optical transition from the valence to the conduction band via the IS and at the same time lower recombination of the photo-generated charges. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.",
journal = "International Journal of Hydrogen Energy",
title = "Enhancing photocatalytic properties of rutile TiO2 by codoping with N and metals - Ab initio study",
volume = "40",
number = "31",
pages = "9696-9703",
doi = "10.1016/j.ijhydene.2015.06.001"
}

Belošević-Čavor, J., Batalović, K., Koteski, V. J., Radaković, J.,& Rangel, C. M.. (2015). Enhancing photocatalytic properties of rutile TiO2 by codoping with N and metals - Ab initio study. in International Journal of Hydrogen Energy, 40(31), 9696-9703.
https://doi.org/10.1016/j.ijhydene.2015.06.001

Belošević-Čavor J, Batalović K, Koteski VJ, Radaković J, Rangel CM. Enhancing photocatalytic properties of rutile TiO2 by codoping with N and metals - Ab initio study. in International Journal of Hydrogen Energy. 2015;40(31):9696-9703.
doi:10.1016/j.ijhydene.2015.06.001 .

Belošević-Čavor, Jelena, Batalović, Katarina, Koteski, Vasil J., Radaković, Jana, Rangel, Carmen Mireya, "Enhancing photocatalytic properties of rutile TiO2 by codoping with N and metals - Ab initio study" in International Journal of Hydrogen Energy, 40, no. 31 (2015):9696-9703,
https://doi.org/10.1016/j.ijhydene.2015.06.001 . .

TY  - JOUR
AU  - Umićević, Ana
AU  - Cekić, Božidar Đ.
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
AU  - Papendorf, Benjamin
AU  - Riedel, Ralf
AU  - Ionescu, Emanuel
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/185
AB  - The evolution of the environment of Hf sites in a hafnium-alkoxide-modified polysilsesquioxane upon polymer-to-ceramic transformation was investigated via the perturbed angular correlation (PAC) method. The results of the PAC measurements on samples thermally treated at temperatures from 400 to 1300 degrees C indicate that Hf is surrounded only by oxygen at all studied temperatures. This finding is in agreement with the evolution pathway of polymer-derived SiHfOC ceramics, which were reported to be generated as single-phase amorphous materials upon pyrolysis of alkoxide-modified polysiloxanes and subsequently to phase separate and crystallize towards HfO2/SiOC nanocomposites. Thus, the results presented here support our previous statement that there is a thermodynamic control on the phase separation and crystallization behavior of Si-M-O-C (M = metal) ceramics (Ionescu et al. 96;2013:1899-1903), which in the case of Hf leads to the precipitation and crystallization of hafnia nanoparticles within a SiOC matrix. (C) 2014 Elsevier Ltd. All rights reserved.
T2  - Journal of the European Ceramic Society
T1  - Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study
VL  - 35
IS  - 1
SP  - 29
EP  - 35
DO  - 10.1016/j.jeurceramsoc.2014.08.023
ER  - 

@article{
author = "Umićević, Ana and Cekić, Božidar Đ. and Belošević-Čavor, Jelena and Koteski, Vasil J. and Papendorf, Benjamin and Riedel, Ralf and Ionescu, Emanuel",
year = "2015",
abstract = "The evolution of the environment of Hf sites in a hafnium-alkoxide-modified polysilsesquioxane upon polymer-to-ceramic transformation was investigated via the perturbed angular correlation (PAC) method. The results of the PAC measurements on samples thermally treated at temperatures from 400 to 1300 degrees C indicate that Hf is surrounded only by oxygen at all studied temperatures. This finding is in agreement with the evolution pathway of polymer-derived SiHfOC ceramics, which were reported to be generated as single-phase amorphous materials upon pyrolysis of alkoxide-modified polysiloxanes and subsequently to phase separate and crystallize towards HfO2/SiOC nanocomposites. Thus, the results presented here support our previous statement that there is a thermodynamic control on the phase separation and crystallization behavior of Si-M-O-C (M = metal) ceramics (Ionescu et al. 96;2013:1899-1903), which in the case of Hf leads to the precipitation and crystallization of hafnia nanoparticles within a SiOC matrix. (C) 2014 Elsevier Ltd. All rights reserved.",
journal = "Journal of the European Ceramic Society",
title = "Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study",
volume = "35",
number = "1",
pages = "29-35",
doi = "10.1016/j.jeurceramsoc.2014.08.023"
}

Umićević, A., Cekić, B. Đ., Belošević-Čavor, J., Koteski, V. J., Papendorf, B., Riedel, R.,& Ionescu, E.. (2015). Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study. in Journal of the European Ceramic Society, 35(1), 29-35.
https://doi.org/10.1016/j.jeurceramsoc.2014.08.023

Umićević A, Cekić BĐ, Belošević-Čavor J, Koteski VJ, Papendorf B, Riedel R, Ionescu E. Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study. in Journal of the European Ceramic Society. 2015;35(1):29-35.
doi:10.1016/j.jeurceramsoc.2014.08.023 .

Umićević, Ana, Cekić, Božidar Đ., Belošević-Čavor, Jelena, Koteski, Vasil J., Papendorf, Benjamin, Riedel, Ralf, Ionescu, Emanuel, "Evolution of the local structure at Hf sites in SiHfOC upon ceramization of a hafnium-alkoxide-modified polysilsesquioxane: A perturbed angular correlation study" in Journal of the European Ceramic Society, 35, no. 1 (2015):29-35,
https://doi.org/10.1016/j.jeurceramsoc.2014.08.023 . .

TY  - JOUR
AU  - Batalović, Katarina
AU  - Radaković, Jana
AU  - Koteski, Vasil J.
AU  - Savić, Milijana
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/747
AB  - Thermodynamics of hydride formation is one of the key properties of metal-hydrogen system and determines its applicability. Therefore, numerous researches are focused on the use of first-principles calculations as the predictive tool when investigating the stability of the hydrides. In this paper we use density functional theory to address two-step process of hydride formation in the MNi (M = Ti, Zr, Hf). Through systematic study of experimentally verified and hypothetical hydride phases, we examine the influence of crystal structure and intermetallic composition on electronic structure, stability and bonding of the hydrides. The unique properties and advantages of gamma-phase hydrides having orthorhombic crystal structure (space group Cmcm) for near-ambient hydrogen storage applications are pointed out, as well as the importance of further investigation of the crystal structure of the beta-phase hydrides. Calculated enthalpies of hydride formation/decomposition and desorption temperatures show good agreement with the wide range of experimental data taken from literature, demonstrating predictive power of the used approach for addressing structure-property relationship and giving complete overview of the important representatives of AB class of intermetallic compounds. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
T2  - International Journal of Hydrogen Energy
T1  - Density functional theory guide to structure and thermodynamics of metal hydrides - Case study of (Ti, Zr, Hf)Ni intermetallic compounds
VL  - 40
IS  - 38
SP  - 13029
EP  - 13038
DO  - 10.1016/j.ijhydene.2015.07.142
ER  - 

@article{
author = "Batalović, Katarina and Radaković, Jana and Koteski, Vasil J. and Savić, Milijana",
year = "2015",
abstract = "Thermodynamics of hydride formation is one of the key properties of metal-hydrogen system and determines its applicability. Therefore, numerous researches are focused on the use of first-principles calculations as the predictive tool when investigating the stability of the hydrides. In this paper we use density functional theory to address two-step process of hydride formation in the MNi (M = Ti, Zr, Hf). Through systematic study of experimentally verified and hypothetical hydride phases, we examine the influence of crystal structure and intermetallic composition on electronic structure, stability and bonding of the hydrides. The unique properties and advantages of gamma-phase hydrides having orthorhombic crystal structure (space group Cmcm) for near-ambient hydrogen storage applications are pointed out, as well as the importance of further investigation of the crystal structure of the beta-phase hydrides. Calculated enthalpies of hydride formation/decomposition and desorption temperatures show good agreement with the wide range of experimental data taken from literature, demonstrating predictive power of the used approach for addressing structure-property relationship and giving complete overview of the important representatives of AB class of intermetallic compounds. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.",
journal = "International Journal of Hydrogen Energy",
title = "Density functional theory guide to structure and thermodynamics of metal hydrides - Case study of (Ti, Zr, Hf)Ni intermetallic compounds",
volume = "40",
number = "38",
pages = "13029-13038",
doi = "10.1016/j.ijhydene.2015.07.142"
}

Batalović, K., Radaković, J., Koteski, V. J.,& Savić, M.. (2015). Density functional theory guide to structure and thermodynamics of metal hydrides - Case study of (Ti, Zr, Hf)Ni intermetallic compounds. in International Journal of Hydrogen Energy, 40(38), 13029-13038.
https://doi.org/10.1016/j.ijhydene.2015.07.142

Batalović K, Radaković J, Koteski VJ, Savić M. Density functional theory guide to structure and thermodynamics of metal hydrides - Case study of (Ti, Zr, Hf)Ni intermetallic compounds. in International Journal of Hydrogen Energy. 2015;40(38):13029-13038.
doi:10.1016/j.ijhydene.2015.07.142 .

Batalović, Katarina, Radaković, Jana, Koteski, Vasil J., Savić, Milijana, "Density functional theory guide to structure and thermodynamics of metal hydrides - Case study of (Ti, Zr, Hf)Ni intermetallic compounds" in International Journal of Hydrogen Energy, 40, no. 38 (2015):13029-13038,
https://doi.org/10.1016/j.ijhydene.2015.07.142 . .

TY  - JOUR
AU  - Toprek, Dragan
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/678
AB  - First principles calculations were performed in the framework of the density functional theory (DFF) using the Full Potential-Linear Augment Plane Wave method (FP-LAPW) within the generalized gradient approximation (GGA) to predict the structural, electronic, elastic and thermal properties of NiTi2 intermetallic compound. By using the Wien2k all-electron code, calculations of the ground state and electronic properties such as lattice constants, bulk modulus, presure derivative of bulk modulus, total energies and density of states were also included. The elastic constants and mechanical properties such as Poissons ratio, Youngs modulus and shear modulus are estimated from the calculated elastic constants of the single crystal. Through the quasi-harmonic Debye model, the preasure and temperature dependences of the linear expansion coefficient, bulk modulus and heat capacity have been investigated. Finally, the Debye temperature has been estimated from the average sound velocity according to the predicted polycrystal bulk properties and from the single crystal elastic constants. (C) 2015 Elsevier Ltd. All rights reserved.
T2  - Journal of Physics and Chemistry of Solids
T1  - Ab initio studies of the structural, elastic, electronic and thermal properties of NiTi2 intermetallic
VL  - 85
SP  - 197
EP  - 205
DO  - 10.1016/j.jpcs.2015.05.019
ER  - 

@article{
author = "Toprek, Dragan and Belošević-Čavor, Jelena and Koteski, Vasil J.",
year = "2015",
abstract = "First principles calculations were performed in the framework of the density functional theory (DFF) using the Full Potential-Linear Augment Plane Wave method (FP-LAPW) within the generalized gradient approximation (GGA) to predict the structural, electronic, elastic and thermal properties of NiTi2 intermetallic compound. By using the Wien2k all-electron code, calculations of the ground state and electronic properties such as lattice constants, bulk modulus, presure derivative of bulk modulus, total energies and density of states were also included. The elastic constants and mechanical properties such as Poissons ratio, Youngs modulus and shear modulus are estimated from the calculated elastic constants of the single crystal. Through the quasi-harmonic Debye model, the preasure and temperature dependences of the linear expansion coefficient, bulk modulus and heat capacity have been investigated. Finally, the Debye temperature has been estimated from the average sound velocity according to the predicted polycrystal bulk properties and from the single crystal elastic constants. (C) 2015 Elsevier Ltd. All rights reserved.",
journal = "Journal of Physics and Chemistry of Solids",
title = "Ab initio studies of the structural, elastic, electronic and thermal properties of NiTi2 intermetallic",
volume = "85",
pages = "197-205",
doi = "10.1016/j.jpcs.2015.05.019"
}

Toprek, D., Belošević-Čavor, J.,& Koteski, V. J.. (2015). Ab initio studies of the structural, elastic, electronic and thermal properties of NiTi2 intermetallic. in Journal of Physics and Chemistry of Solids, 85, 197-205.
https://doi.org/10.1016/j.jpcs.2015.05.019

Toprek D, Belošević-Čavor J, Koteski VJ. Ab initio studies of the structural, elastic, electronic and thermal properties of NiTi2 intermetallic. in Journal of Physics and Chemistry of Solids. 2015;85:197-205.
doi:10.1016/j.jpcs.2015.05.019 .

Toprek, Dragan, Belošević-Čavor, Jelena, Koteski, Vasil J., "Ab initio studies of the structural, elastic, electronic and thermal properties of NiTi2 intermetallic" in Journal of Physics and Chemistry of Solids, 85 (2015):197-205,
https://doi.org/10.1016/j.jpcs.2015.05.019 . .

TY  - JOUR
AU  - Koteski, Vasil J.
AU  - Belošević-Čavor, Jelena
AU  - Batalović, Katarina
AU  - Radaković, Jana
AU  - Umićević, Ana
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/254
AB  - Incorporation of suitable dopants in MgH2 is widely investigated as the way of improving hydrogen storage characteristics of this material. The catalytic role of transition metal dopants on hydrogen desorption from MgH2 is very promising, but further attention is required in order to optimize the experimental methods and design materials with desired properties. In this paper we investigate the role of Ti, Fe, and Mn on the transport properties of hydrogen in MgH2, which are marked as limiting factor in the effort to lower the hydrogen desorption temperature. Taking into account the lattice relaxation around the impurities, we consider a number of different diffusion paths in the pure and doped system. Using PAW DFT calculations in combination with the NEB method, we demonstrate that the diffusion of the most relevant positively charged hydrogen vacancy and negatively charged interstitial hydrogen atom is locally hindered by the presence of the impurity atoms.
T2  - RSC Advances
T1  - Hydrogen diffusion in MgH2 doped with Ti, Mn and Fe
VL  - 5
IS  - 44
SP  - 34894
EP  - 34899
DO  - 10.1039/c5ra04168f
ER  - 

@article{
author = "Koteski, Vasil J. and Belošević-Čavor, Jelena and Batalović, Katarina and Radaković, Jana and Umićević, Ana",
year = "2015",
abstract = "Incorporation of suitable dopants in MgH2 is widely investigated as the way of improving hydrogen storage characteristics of this material. The catalytic role of transition metal dopants on hydrogen desorption from MgH2 is very promising, but further attention is required in order to optimize the experimental methods and design materials with desired properties. In this paper we investigate the role of Ti, Fe, and Mn on the transport properties of hydrogen in MgH2, which are marked as limiting factor in the effort to lower the hydrogen desorption temperature. Taking into account the lattice relaxation around the impurities, we consider a number of different diffusion paths in the pure and doped system. Using PAW DFT calculations in combination with the NEB method, we demonstrate that the diffusion of the most relevant positively charged hydrogen vacancy and negatively charged interstitial hydrogen atom is locally hindered by the presence of the impurity atoms.",
journal = "RSC Advances",
title = "Hydrogen diffusion in MgH2 doped with Ti, Mn and Fe",
volume = "5",
number = "44",
pages = "34894-34899",
doi = "10.1039/c5ra04168f"
}

Koteski, V. J., Belošević-Čavor, J., Batalović, K., Radaković, J.,& Umićević, A.. (2015). Hydrogen diffusion in MgH2 doped with Ti, Mn and Fe. in RSC Advances, 5(44), 34894-34899.
https://doi.org/10.1039/c5ra04168f

Koteski VJ, Belošević-Čavor J, Batalović K, Radaković J, Umićević A. Hydrogen diffusion in MgH2 doped with Ti, Mn and Fe. in RSC Advances. 2015;5(44):34894-34899.
doi:10.1039/c5ra04168f .

Koteski, Vasil J., Belošević-Čavor, Jelena, Batalović, Katarina, Radaković, Jana, Umićević, Ana, "Hydrogen diffusion in MgH2 doped with Ti, Mn and Fe" in RSC Advances, 5, no. 44 (2015):34894-34899,
https://doi.org/10.1039/c5ra04168f . .

TY  - JOUR
AU  - Batalović, Katarina
AU  - Radaković, Jana
AU  - Belošević-Čavor, Jelena
AU  - Koteski, Vasil J.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6034
AB  - Mg2FeH6 is a promising hydrogen storage material with one of the highest volumetric hydrogen density among the known hydrogen storage materials. However, its complicated synthesis and high temperature of hydrogen desorption limit wider applications. In this paper we study the influence of transition metal (Ni, Co, Mn) doping on the structural, electronic and hydrogen sorption properties of Mg2FeH6, using first-principles density functional theory calculations. The thermodynamics of three different synthesis routes is addressed, and all of the mentioned transition metals are found to destabilize Mg2FeH6. In addition, a detailed study of electronic structure properties, including densities of states (DOS) and charge transfer analysis (AIM), reveals that the doping with Ni, Mn and Co leads to the reduction of the direct band gap of Mg2FeH6.
T2  - Physical Chemistry Chemical Physics
T1  - Transition metal doping of Mg2FeH6 - a DFT insight into synthesis and electronic structure
VL  - 16
IS  - 24
SP  - 12356
EP  - 12361
DO  - 10.1039/c4cp01020e
ER  - 

@article{
author = "Batalović, Katarina and Radaković, Jana and Belošević-Čavor, Jelena and Koteski, Vasil J.",
year = "2014",
abstract = "Mg2FeH6 is a promising hydrogen storage material with one of the highest volumetric hydrogen density among the known hydrogen storage materials. However, its complicated synthesis and high temperature of hydrogen desorption limit wider applications. In this paper we study the influence of transition metal (Ni, Co, Mn) doping on the structural, electronic and hydrogen sorption properties of Mg2FeH6, using first-principles density functional theory calculations. The thermodynamics of three different synthesis routes is addressed, and all of the mentioned transition metals are found to destabilize Mg2FeH6. In addition, a detailed study of electronic structure properties, including densities of states (DOS) and charge transfer analysis (AIM), reveals that the doping with Ni, Mn and Co leads to the reduction of the direct band gap of Mg2FeH6.",
journal = "Physical Chemistry Chemical Physics",
title = "Transition metal doping of Mg2FeH6 - a DFT insight into synthesis and electronic structure",
volume = "16",
number = "24",
pages = "12356-12361",
doi = "10.1039/c4cp01020e"
}

Batalović, K., Radaković, J., Belošević-Čavor, J.,& Koteski, V. J.. (2014). Transition metal doping of Mg2FeH6 - a DFT insight into synthesis and electronic structure. in Physical Chemistry Chemical Physics, 16(24), 12356-12361.
https://doi.org/10.1039/c4cp01020e

Batalović K, Radaković J, Belošević-Čavor J, Koteski VJ. Transition metal doping of Mg2FeH6 - a DFT insight into synthesis and electronic structure. in Physical Chemistry Chemical Physics. 2014;16(24):12356-12361.
doi:10.1039/c4cp01020e .

Batalović, Katarina, Radaković, Jana, Belošević-Čavor, Jelena, Koteski, Vasil J., "Transition metal doping of Mg2FeH6 - a DFT insight into synthesis and electronic structure" in Physical Chemistry Chemical Physics, 16, no. 24 (2014):12356-12361,
https://doi.org/10.1039/c4cp01020e . .