TY  - JOUR
AU  - Marušić, Leonardo
AU  - Kalinić, Ana
AU  - Radović, Ivan
AU  - Jakovac, Josip
AU  - Mišković, Zoran L.
AU  - Despoja, Vito
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10245
AB  - Graphene doped by alkali atoms (ACx) supports two heavily populated bands (π and σ) crossing the Fermi level, which enables the formation of two intense two-dimensional plasmons: the Dirac plasmon (DP) and the acoustic plasmon (AP). Although the mechanism of the formation of these plasmons in electrostatically biased graphene or at noble metal surfaces is well known, the mechanism of their formation in alkali-doped graphenes is still not completely understood. We shall demonstrate that two isoelectronic systems, KC8 and CsC8, support substantially different plasmonic spectra: the KC8 supports a sharp DP and a well-defined AP, while the CsC8 supports a broad DP and does not support an AP at all. We shall demonstrate that the AP in an ACx is not, as previously believed, just a consequence of the interplay of the π and σ intraband transitions, but a very subtle interplay between these transitions and the background screening, caused by the out-of-plane interband C(π)→A(σ) transitions.
T2  - International Journal of Molecular Sciences
T1  - Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals
VL  - 23
IS  - 9
SP  - 4770
DO  - 10.3390/ijms23094770
ER  - 

@article{
author = "Marušić, Leonardo and Kalinić, Ana and Radović, Ivan and Jakovac, Josip and Mišković, Zoran L. and Despoja, Vito",
year = "2022",
abstract = "Graphene doped by alkali atoms (ACx) supports two heavily populated bands (π and σ) crossing the Fermi level, which enables the formation of two intense two-dimensional plasmons: the Dirac plasmon (DP) and the acoustic plasmon (AP). Although the mechanism of the formation of these plasmons in electrostatically biased graphene or at noble metal surfaces is well known, the mechanism of their formation in alkali-doped graphenes is still not completely understood. We shall demonstrate that two isoelectronic systems, KC8 and CsC8, support substantially different plasmonic spectra: the KC8 supports a sharp DP and a well-defined AP, while the CsC8 supports a broad DP and does not support an AP at all. We shall demonstrate that the AP in an ACx is not, as previously believed, just a consequence of the interplay of the π and σ intraband transitions, but a very subtle interplay between these transitions and the background screening, caused by the out-of-plane interband C(π)→A(σ) transitions.",
journal = "International Journal of Molecular Sciences",
title = "Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals",
volume = "23",
number = "9",
pages = "4770",
doi = "10.3390/ijms23094770"
}

Marušić, L., Kalinić, A., Radović, I., Jakovac, J., Mišković, Z. L.,& Despoja, V.. (2022). Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals. in International Journal of Molecular Sciences, 23(9), 4770.
https://doi.org/10.3390/ijms23094770

Marušić L, Kalinić A, Radović I, Jakovac J, Mišković ZL, Despoja V. Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals. in International Journal of Molecular Sciences. 2022;23(9):4770.
doi:10.3390/ijms23094770 .

Marušić, Leonardo, Kalinić, Ana, Radović, Ivan, Jakovac, Josip, Mišković, Zoran L., Despoja, Vito, "Resolving the Mechanism of Acoustic Plasmon Instability in Graphene Doped by Alkali Metals" in International Journal of Molecular Sciences, 23, no. 9 (2022):4770,
https://doi.org/10.3390/ijms23094770 . .

TY  - JOUR
AU  - Kalinić, Ana
AU  - Despoja, Vito
AU  - Radović, Ivan
AU  - Karbunar, Lazar
AU  - Mišković, Zoran L.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10453
AB  - We study the impact of plasmon-phonon hybridization on the stopping and image forces acting on a charged particle moving parallel to a graphene-Al2O3-graphene sandwichlike composite system by considering a broad domain in the parameter space. The effective dielectric function of the system is obtained using two descriptions of the electronic response of doped graphene: an ab initio method based on the time-dependent density functional theory calculations and an analytical expression based on the massless Dirac fermion (MDF) approximation for graphene π bands. It is found that the main discrepancies between the two methods come from the high-energy interband electron transitions, which are included in the ab initio method but not in the MDF method. Special attention is paid to the regime of low-particle speeds, where the MDF method compares well with the ab initio method, but the modeling is sensitive to the effects of finite temperature and the treatment of phenomenological damping. It is observed at low particle speeds that both forces exhibit an interesting interplay between the hybrid modes of the phononic type and the continuum of the intraband electron-hole excitations in graphene. Furthermore, the effects of the lowest-energy antisymmetric modes, which exhibit acoustic dispersions at long wavelengths in a system with equally doped graphene layers, are exposed in calculations of the stopping force on a co-moving pair of incident particles with opposite charges that are symmetrically positioned around the target system.
T2  - Physical Review B
T1  - Stopping and image forces acting on a charged particle moving near a graphene-Al2O3-graphene heterostructure
VL  - 106
IS  - 11
SP  - 115430
DO  - 10.1103/PhysRevB.106.115430
ER  - 

@article{
author = "Kalinić, Ana and Despoja, Vito and Radović, Ivan and Karbunar, Lazar and Mišković, Zoran L.",
year = "2022",
abstract = "We study the impact of plasmon-phonon hybridization on the stopping and image forces acting on a charged particle moving parallel to a graphene-Al2O3-graphene sandwichlike composite system by considering a broad domain in the parameter space. The effective dielectric function of the system is obtained using two descriptions of the electronic response of doped graphene: an ab initio method based on the time-dependent density functional theory calculations and an analytical expression based on the massless Dirac fermion (MDF) approximation for graphene π bands. It is found that the main discrepancies between the two methods come from the high-energy interband electron transitions, which are included in the ab initio method but not in the MDF method. Special attention is paid to the regime of low-particle speeds, where the MDF method compares well with the ab initio method, but the modeling is sensitive to the effects of finite temperature and the treatment of phenomenological damping. It is observed at low particle speeds that both forces exhibit an interesting interplay between the hybrid modes of the phononic type and the continuum of the intraband electron-hole excitations in graphene. Furthermore, the effects of the lowest-energy antisymmetric modes, which exhibit acoustic dispersions at long wavelengths in a system with equally doped graphene layers, are exposed in calculations of the stopping force on a co-moving pair of incident particles with opposite charges that are symmetrically positioned around the target system.",
journal = "Physical Review B",
title = "Stopping and image forces acting on a charged particle moving near a graphene-Al2O3-graphene heterostructure",
volume = "106",
number = "11",
pages = "115430",
doi = "10.1103/PhysRevB.106.115430"
}

Kalinić, A., Despoja, V., Radović, I., Karbunar, L.,& Mišković, Z. L.. (2022). Stopping and image forces acting on a charged particle moving near a graphene-Al2O3-graphene heterostructure. in Physical Review B, 106(11), 115430.
https://doi.org/10.1103/PhysRevB.106.115430

Kalinić A, Despoja V, Radović I, Karbunar L, Mišković ZL. Stopping and image forces acting on a charged particle moving near a graphene-Al2O3-graphene heterostructure. in Physical Review B. 2022;106(11):115430.
doi:10.1103/PhysRevB.106.115430 .

Kalinić, Ana, Despoja, Vito, Radović, Ivan, Karbunar, Lazar, Mišković, Zoran L., "Stopping and image forces acting on a charged particle moving near a graphene-Al2O3-graphene heterostructure" in Physical Review B, 106, no. 11 (2022):115430,
https://doi.org/10.1103/PhysRevB.106.115430 . .

TY  - JOUR
AU  - Bai, Xiang-Jia
AU  - Zhang, Ying-Ying
AU  - Mišković, Zoran L.
AU  - Radović, Ivan
AU  - Li, Chun-Zhi
AU  - Song, Yuan-Hong
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9552
AB  - We analyze the effects of the strain-induced pseudomagnetic field on the subthreshold mechanism of hybridization taking place between the Dirac plasmon in graphene and the surface optical phonon modes in a nearby substrate. It is shown that the pseudomagnetic field exerts quite strong influence on the oscillatory pattern in the total potential in the plane of graphene, as well as on the stopping and the image forces on a charge, which moves parallel to the graphene at a speed below the Fermi velocity, specially for small graphene–substrate gap sizes. One may conclude that the subthreshold mechanism of the plasmon–phonon hybridization can be controlled by varying the pseudomagnetic field strength and the doping density in graphene. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.
T2  - Plasmonics
T1  - The Effects of Pseudomagnetic Fields on Plasmon–Phonon Hybridization in Supported Graphene Probed by a Moving Charged Particle
VL  - 16
IS  - 4
SP  - 1089
EP  - 1098
DO  - 10.1007/s11468-020-01369-3
ER  - 

@article{
author = "Bai, Xiang-Jia and Zhang, Ying-Ying and Mišković, Zoran L. and Radović, Ivan and Li, Chun-Zhi and Song, Yuan-Hong",
year = "2021",
abstract = "We analyze the effects of the strain-induced pseudomagnetic field on the subthreshold mechanism of hybridization taking place between the Dirac plasmon in graphene and the surface optical phonon modes in a nearby substrate. It is shown that the pseudomagnetic field exerts quite strong influence on the oscillatory pattern in the total potential in the plane of graphene, as well as on the stopping and the image forces on a charge, which moves parallel to the graphene at a speed below the Fermi velocity, specially for small graphene–substrate gap sizes. One may conclude that the subthreshold mechanism of the plasmon–phonon hybridization can be controlled by varying the pseudomagnetic field strength and the doping density in graphene. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.",
journal = "Plasmonics",
title = "The Effects of Pseudomagnetic Fields on Plasmon–Phonon Hybridization in Supported Graphene Probed by a Moving Charged Particle",
volume = "16",
number = "4",
pages = "1089-1098",
doi = "10.1007/s11468-020-01369-3"
}

Bai, X., Zhang, Y., Mišković, Z. L., Radović, I., Li, C.,& Song, Y.. (2021). The Effects of Pseudomagnetic Fields on Plasmon–Phonon Hybridization in Supported Graphene Probed by a Moving Charged Particle. in Plasmonics, 16(4), 1089-1098.
https://doi.org/10.1007/s11468-020-01369-3

Bai X, Zhang Y, Mišković ZL, Radović I, Li C, Song Y. The Effects of Pseudomagnetic Fields on Plasmon–Phonon Hybridization in Supported Graphene Probed by a Moving Charged Particle. in Plasmonics. 2021;16(4):1089-1098.
doi:10.1007/s11468-020-01369-3 .

Bai, Xiang-Jia, Zhang, Ying-Ying, Mišković, Zoran L., Radović, Ivan, Li, Chun-Zhi, Song, Yuan-Hong, "The Effects of Pseudomagnetic Fields on Plasmon–Phonon Hybridization in Supported Graphene Probed by a Moving Charged Particle" in Plasmonics, 16, no. 4 (2021):1089-1098,
https://doi.org/10.1007/s11468-020-01369-3 . .

TY  - JOUR
AU  - Đorđević, Tijana
AU  - Radović, Ivan
AU  - Despoja, Vito
AU  - Lyon, Keenan
AU  - Borka, Duško
AU  - Mišković, Zoran L.
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1831
AB  - We present an analytical modeling of the electron energy loss (EEL) spectroscopy data for free-standing graphene obtained by scanning transmission electron microscope. The probability density for energy loss of fast electrons traversing graphene under normal incidence is evaluated using an optical approximation based on the conductivity of graphene given in the local, i.e., frequency-dependent form derived by both a two-dimensional, two-fluid extended hydrodynamic (eHD) model and an ab initio method. We compare the results for the real and imaginary parts of the optical conductivity in graphene obtained by these two methods. The calculated probability density is directly compared with the EEL spectra from three independent experiments and we find very good agreement, especially in the case of the eHD model. Furthermore, we point out that the subtraction of the zero-loss peak from the experimental EEL spectra has a strong influence on the analytical model for the EEL spectroscopy data. (C) 2017 Elsevier B.V. All rights reserved.
T2  - Ultramicroscopy
T1  - Analytical modeling of electron energy loss spectroscopy of graphene: Ab initio study versus extended hydrodynamic model
VL  - 184
SP  - 134
EP  - 142
DO  - 10.1016/j.ultramic.2017.08.014
ER  - 

@article{
author = "Đorđević, Tijana and Radović, Ivan and Despoja, Vito and Lyon, Keenan and Borka, Duško and Mišković, Zoran L.",
year = "2018",
abstract = "We present an analytical modeling of the electron energy loss (EEL) spectroscopy data for free-standing graphene obtained by scanning transmission electron microscope. The probability density for energy loss of fast electrons traversing graphene under normal incidence is evaluated using an optical approximation based on the conductivity of graphene given in the local, i.e., frequency-dependent form derived by both a two-dimensional, two-fluid extended hydrodynamic (eHD) model and an ab initio method. We compare the results for the real and imaginary parts of the optical conductivity in graphene obtained by these two methods. The calculated probability density is directly compared with the EEL spectra from three independent experiments and we find very good agreement, especially in the case of the eHD model. Furthermore, we point out that the subtraction of the zero-loss peak from the experimental EEL spectra has a strong influence on the analytical model for the EEL spectroscopy data. (C) 2017 Elsevier B.V. All rights reserved.",
journal = "Ultramicroscopy",
title = "Analytical modeling of electron energy loss spectroscopy of graphene: Ab initio study versus extended hydrodynamic model",
volume = "184",
pages = "134-142",
doi = "10.1016/j.ultramic.2017.08.014"
}

Đorđević, T., Radović, I., Despoja, V., Lyon, K., Borka, D.,& Mišković, Z. L.. (2018). Analytical modeling of electron energy loss spectroscopy of graphene: Ab initio study versus extended hydrodynamic model. in Ultramicroscopy, 184, 134-142.
https://doi.org/10.1016/j.ultramic.2017.08.014

Đorđević T, Radović I, Despoja V, Lyon K, Borka D, Mišković ZL. Analytical modeling of electron energy loss spectroscopy of graphene: Ab initio study versus extended hydrodynamic model. in Ultramicroscopy. 2018;184:134-142.
doi:10.1016/j.ultramic.2017.08.014 .

Đorđević, Tijana, Radović, Ivan, Despoja, Vito, Lyon, Keenan, Borka, Duško, Mišković, Zoran L., "Analytical modeling of electron energy loss spectroscopy of graphene: Ab initio study versus extended hydrodynamic model" in Ultramicroscopy, 184 (2018):134-142,
https://doi.org/10.1016/j.ultramic.2017.08.014 . .

TY  - JOUR
AU  - Radović, Ivan
AU  - Song, Yuan-Hong
AU  - Zhang, Ying-Ying
AU  - Borka, Duško
AU  - Mišković, Zoran L.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1518
AB  - We use the dielectric response formalism to explore the wake effect due to excitation of the sheet plasmons in graphene and in a two-dimensional (2D) electron gas with a parabolic energy band, caused by an externally moving charged particle. Using the random phase approximation to obtain the relevant polarisation functions, we have found similarities as well as some differences in the V-shaped wake patterns that result from different structures of the single-particle excitation spectra in those two electron systems. While both systems exhibit a velocity threshold for the charged particle to be able to excite a wake, graphene shows some irregularities in the wake oscillations behind that particle, whereas the 2D electron gas exhibits a larger opening angle of its V-shaped wake.
T2  - Radiation Effects and Defects in Solids
T1  - Excitation of plasmon wakes in two-dimensional electron systems by moving external charged particles
VL  - 172
IS  - 1-2
SP  - 90
EP  - 99
DO  - 10.1080/10420150.2017.1286661
ER  - 

@article{
author = "Radović, Ivan and Song, Yuan-Hong and Zhang, Ying-Ying and Borka, Duško and Mišković, Zoran L.",
year = "2017",
abstract = "We use the dielectric response formalism to explore the wake effect due to excitation of the sheet plasmons in graphene and in a two-dimensional (2D) electron gas with a parabolic energy band, caused by an externally moving charged particle. Using the random phase approximation to obtain the relevant polarisation functions, we have found similarities as well as some differences in the V-shaped wake patterns that result from different structures of the single-particle excitation spectra in those two electron systems. While both systems exhibit a velocity threshold for the charged particle to be able to excite a wake, graphene shows some irregularities in the wake oscillations behind that particle, whereas the 2D electron gas exhibits a larger opening angle of its V-shaped wake.",
journal = "Radiation Effects and Defects in Solids",
title = "Excitation of plasmon wakes in two-dimensional electron systems by moving external charged particles",
volume = "172",
number = "1-2",
pages = "90-99",
doi = "10.1080/10420150.2017.1286661"
}

Radović, I., Song, Y., Zhang, Y., Borka, D.,& Mišković, Z. L.. (2017). Excitation of plasmon wakes in two-dimensional electron systems by moving external charged particles. in Radiation Effects and Defects in Solids, 172(1-2), 90-99.
https://doi.org/10.1080/10420150.2017.1286661

Radović I, Song Y, Zhang Y, Borka D, Mišković ZL. Excitation of plasmon wakes in two-dimensional electron systems by moving external charged particles. in Radiation Effects and Defects in Solids. 2017;172(1-2):90-99.
doi:10.1080/10420150.2017.1286661 .

Radović, Ivan, Song, Yuan-Hong, Zhang, Ying-Ying, Borka, Duško, Mišković, Zoran L., "Excitation of plasmon wakes in two-dimensional electron systems by moving external charged particles" in Radiation Effects and Defects in Solids, 172, no. 1-2 (2017):90-99,
https://doi.org/10.1080/10420150.2017.1286661 . .

TY  - JOUR
AU  - Zhang, Ying-Ying
AU  - Song, Yuan-Hong
AU  - Radović, Ivan
AU  - Mišković, Zoran L.
AU  - Wang, You-Nian
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1706
AB  - We study plasmon excitations and channeling trajectories of charged particles in triple-walled carbon nanotubes (TWNTs) based on a semi-classical kinetic model combined with the Molecular Dynamics method. Numerical results show that the outer and inner tubes of a TWNT exert strong influence on the peak structures of the self-energy (or the image potential) and the stopping power curves for the channeling ion, resulting in one or two narrow peaks in the low speed region. In addition, the radial dependencies of the total potential, which includes the image potential due to dynamic polarization of the electron gas in nanotubes and a reactive empirical bond order potential for atomic interactions, are compared for single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes (DWNTs) and TWNTs. By comparing the ion channeling trajectories in those types of nanotubes, we conclude that the variation of the total energy of ions with their channeling distance along the nanotube axis is related to the types of channeling trajectories, exhibiting smooth helical shapes in TWNTs and a succession of sharp reflections off the wall in SWNTs and DWNTs.
T2  - European Physical Journal D. Atoms, Molecules, Clusters and Optical Physics
T1  - Interactions of moving charged particles with triple-walled carbon nanotubes
VL  - 71
IS  - 8
DO  - 10.1140/epjd/e2017-70744-3
ER  - 

@article{
author = "Zhang, Ying-Ying and Song, Yuan-Hong and Radović, Ivan and Mišković, Zoran L. and Wang, You-Nian",
year = "2017",
abstract = "We study plasmon excitations and channeling trajectories of charged particles in triple-walled carbon nanotubes (TWNTs) based on a semi-classical kinetic model combined with the Molecular Dynamics method. Numerical results show that the outer and inner tubes of a TWNT exert strong influence on the peak structures of the self-energy (or the image potential) and the stopping power curves for the channeling ion, resulting in one or two narrow peaks in the low speed region. In addition, the radial dependencies of the total potential, which includes the image potential due to dynamic polarization of the electron gas in nanotubes and a reactive empirical bond order potential for atomic interactions, are compared for single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes (DWNTs) and TWNTs. By comparing the ion channeling trajectories in those types of nanotubes, we conclude that the variation of the total energy of ions with their channeling distance along the nanotube axis is related to the types of channeling trajectories, exhibiting smooth helical shapes in TWNTs and a succession of sharp reflections off the wall in SWNTs and DWNTs.",
journal = "European Physical Journal D. Atoms, Molecules, Clusters and Optical Physics",
title = "Interactions of moving charged particles with triple-walled carbon nanotubes",
volume = "71",
number = "8",
doi = "10.1140/epjd/e2017-70744-3"
}

Zhang, Y., Song, Y., Radović, I., Mišković, Z. L.,& Wang, Y.. (2017). Interactions of moving charged particles with triple-walled carbon nanotubes. in European Physical Journal D. Atoms, Molecules, Clusters and Optical Physics, 71(8).
https://doi.org/10.1140/epjd/e2017-70744-3

Zhang Y, Song Y, Radović I, Mišković ZL, Wang Y. Interactions of moving charged particles with triple-walled carbon nanotubes. in European Physical Journal D. Atoms, Molecules, Clusters and Optical Physics. 2017;71(8).
doi:10.1140/epjd/e2017-70744-3 .

Zhang, Ying-Ying, Song, Yuan-Hong, Radović, Ivan, Mišković, Zoran L., Wang, You-Nian, "Interactions of moving charged particles with triple-walled carbon nanotubes" in European Physical Journal D. Atoms, Molecules, Clusters and Optical Physics, 71, no. 8 (2017),
https://doi.org/10.1140/epjd/e2017-70744-3 . .

TY  - JOUR
AU  - Despoja, Vito
AU  - Đorđević, Tijana
AU  - Karbunar, Lazar
AU  - Radović, Ivan
AU  - Mišković, Zoran L.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1693
AB  - The propagator of a dynamically screened Coulomb interaction W in a sandwichlike structure consisting of two graphene layers separated by a slab of Al2O3 (or vacuum) is derived from single-layer graphene response functions and by using a local dielectric function for the bulk Al2O3. The response function of graphene is obtained using two approaches within the random phase approximation (RPA): an ab initio method that includes all electronic bands in graphene and a computationally less demanding method based on the massless Dirac fermion (MDF) approximation for the low-energy excitations of electrons in the p bands. The propagator W is used to derive an expression for the effective dielectric function of our sandwich structure, which is relevant for the reflection electron energy loss spectroscopy of its surface. Focusing on the range of frequencies from THz to mid-infrared, special attention is paid to finding an accurate optical limit in the ab initio method, where the response function is expressed in terms of a frequency-dependent conductivity of graphene. It was shown that the optical limit suffices for describing hybridization between the Dirac plasmons in graphene layers and the Fuchs-Kliewer phonons in both surfaces of the Al2O3 slab, and that the spectra obtained from both the ab initio method and the MDF approximation in the optical limit agree perfectly well for wave numbers up to about 0.1 nm(-1). Going beyond the optical limit, the agreement between the full ab initio method and the MDF approximation was found to extend to wave numbers up to about 0.3 nm(-1) for doped graphene layers with the Fermi energy of 0.2 eV.
T2  - Physical Review B: Condensed Matter and Materials Physics
T1  - Ab initio study of the electron energy loss function in a graphene-sapphire-graphene composite system
VL  - 96
IS  - 7
DO  - 10.1103/PhysRevB.96.075433
ER  - 

@article{
author = "Despoja, Vito and Đorđević, Tijana and Karbunar, Lazar and Radović, Ivan and Mišković, Zoran L.",
year = "2017",
abstract = "The propagator of a dynamically screened Coulomb interaction W in a sandwichlike structure consisting of two graphene layers separated by a slab of Al2O3 (or vacuum) is derived from single-layer graphene response functions and by using a local dielectric function for the bulk Al2O3. The response function of graphene is obtained using two approaches within the random phase approximation (RPA): an ab initio method that includes all electronic bands in graphene and a computationally less demanding method based on the massless Dirac fermion (MDF) approximation for the low-energy excitations of electrons in the p bands. The propagator W is used to derive an expression for the effective dielectric function of our sandwich structure, which is relevant for the reflection electron energy loss spectroscopy of its surface. Focusing on the range of frequencies from THz to mid-infrared, special attention is paid to finding an accurate optical limit in the ab initio method, where the response function is expressed in terms of a frequency-dependent conductivity of graphene. It was shown that the optical limit suffices for describing hybridization between the Dirac plasmons in graphene layers and the Fuchs-Kliewer phonons in both surfaces of the Al2O3 slab, and that the spectra obtained from both the ab initio method and the MDF approximation in the optical limit agree perfectly well for wave numbers up to about 0.1 nm(-1). Going beyond the optical limit, the agreement between the full ab initio method and the MDF approximation was found to extend to wave numbers up to about 0.3 nm(-1) for doped graphene layers with the Fermi energy of 0.2 eV.",
journal = "Physical Review B: Condensed Matter and Materials Physics",
title = "Ab initio study of the electron energy loss function in a graphene-sapphire-graphene composite system",
volume = "96",
number = "7",
doi = "10.1103/PhysRevB.96.075433"
}

Despoja, V., Đorđević, T., Karbunar, L., Radović, I.,& Mišković, Z. L.. (2017). Ab initio study of the electron energy loss function in a graphene-sapphire-graphene composite system. in Physical Review B: Condensed Matter and Materials Physics, 96(7).
https://doi.org/10.1103/PhysRevB.96.075433

Despoja V, Đorđević T, Karbunar L, Radović I, Mišković ZL. Ab initio study of the electron energy loss function in a graphene-sapphire-graphene composite system. in Physical Review B: Condensed Matter and Materials Physics. 2017;96(7).
doi:10.1103/PhysRevB.96.075433 .

Despoja, Vito, Đorđević, Tijana, Karbunar, Lazar, Radović, Ivan, Mišković, Zoran L., "Ab initio study of the electron energy loss function in a graphene-sapphire-graphene composite system" in Physical Review B: Condensed Matter and Materials Physics, 96, no. 7 (2017),
https://doi.org/10.1103/PhysRevB.96.075433 . .

TY  - JOUR
AU  - Karbunar, Lazar
AU  - Borka, Duško
AU  - Radović, Ivan
AU  - Mišković, Zoran L.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1066
AB  - We investigate the interactions of charged particles with straight and bent single-walled carbon nanotubes (SWNTs) under channeling conditions in the presence of dynamic polarization of the valence electrons in carbon. This polarization is described by a cylindrical, two-fluid hydrodynamic model with the parameters taken from the recent modelling of several independent experiments on electron energy loss spectroscopy of carbon nano-structures. We use the hydrodynamic model to calculate the image potential for protons moving through four types of SWNTs at a speed of 3 atomic units. The image potential is then combined with the Doyle-Turner atomic potential to obtain the total potential in the bent carbon nanotubes. Using that potential, we also compute the spatial and angular distributions of protons channeled through the bent carbon nanotubes, and compare the results with the distributions obtained without taking into account the image potential.
T2  - Chinese Physics B
T1  - Channeling of fast ions through the bent carbon nanotubes: The extended two-fluid hydrodynamic model
VL  - 25
IS  - 4
DO  - 10.1088/1674-1056/25/4/046106
ER  - 

@article{
author = "Karbunar, Lazar and Borka, Duško and Radović, Ivan and Mišković, Zoran L.",
year = "2016",
abstract = "We investigate the interactions of charged particles with straight and bent single-walled carbon nanotubes (SWNTs) under channeling conditions in the presence of dynamic polarization of the valence electrons in carbon. This polarization is described by a cylindrical, two-fluid hydrodynamic model with the parameters taken from the recent modelling of several independent experiments on electron energy loss spectroscopy of carbon nano-structures. We use the hydrodynamic model to calculate the image potential for protons moving through four types of SWNTs at a speed of 3 atomic units. The image potential is then combined with the Doyle-Turner atomic potential to obtain the total potential in the bent carbon nanotubes. Using that potential, we also compute the spatial and angular distributions of protons channeled through the bent carbon nanotubes, and compare the results with the distributions obtained without taking into account the image potential.",
journal = "Chinese Physics B",
title = "Channeling of fast ions through the bent carbon nanotubes: The extended two-fluid hydrodynamic model",
volume = "25",
number = "4",
doi = "10.1088/1674-1056/25/4/046106"
}

Karbunar, L., Borka, D., Radović, I.,& Mišković, Z. L.. (2016). Channeling of fast ions through the bent carbon nanotubes: The extended two-fluid hydrodynamic model. in Chinese Physics B, 25(4).
https://doi.org/10.1088/1674-1056/25/4/046106

Karbunar L, Borka D, Radović I, Mišković ZL. Channeling of fast ions through the bent carbon nanotubes: The extended two-fluid hydrodynamic model. in Chinese Physics B. 2016;25(4).
doi:10.1088/1674-1056/25/4/046106 .

Karbunar, Lazar, Borka, Duško, Radović, Ivan, Mišković, Zoran L., "Channeling of fast ions through the bent carbon nanotubes: The extended two-fluid hydrodynamic model" in Chinese Physics B, 25, no. 4 (2016),
https://doi.org/10.1088/1674-1056/25/4/046106 . .

TY  - JOUR
AU  - Marinković, Tijana
AU  - Radović, Ivan
AU  - Borka, Duško
AU  - Mišković, Zoran L.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/810
AB  - We use the dielectric response formalism to show how an incident charged particle may be used to probe the hybridization taking place between the Dirac plasmon in graphene and the surface optical phonon modes in a SiO2 substrate. Strong effects of this hybridization are found in the wake pattern in the induced potential, as well as in the stopping and image forces that act on the incident charge in a broad range of its velocities. Particularly intriguing is the possibility to control the plasmon-phonon hybridization by varying the doping density of graphene, where the regime of a nominally neutral graphene is expected to give rise to dramatic effects in the energy loss of charged particles that move at the velocities below the Fermi velocity of graphene.
PB  - Springer Nature
T2  - Plasmonics
T1  - Probing the Plasmon-Phonon Hybridization in Supported Graphene by Externally Moving Charged Particles
VL  - 10
IS  - 6
SP  - 1741
EP  - 1749
DO  - 10.1007/s11468-015-9993-3
ER  - 

@article{
author = "Marinković, Tijana and Radović, Ivan and Borka, Duško and Mišković, Zoran L.",
year = "2015",
abstract = "We use the dielectric response formalism to show how an incident charged particle may be used to probe the hybridization taking place between the Dirac plasmon in graphene and the surface optical phonon modes in a SiO2 substrate. Strong effects of this hybridization are found in the wake pattern in the induced potential, as well as in the stopping and image forces that act on the incident charge in a broad range of its velocities. Particularly intriguing is the possibility to control the plasmon-phonon hybridization by varying the doping density of graphene, where the regime of a nominally neutral graphene is expected to give rise to dramatic effects in the energy loss of charged particles that move at the velocities below the Fermi velocity of graphene.",
publisher = "Springer Nature",
journal = "Plasmonics",
title = "Probing the Plasmon-Phonon Hybridization in Supported Graphene by Externally Moving Charged Particles",
volume = "10",
number = "6",
pages = "1741-1749",
doi = "10.1007/s11468-015-9993-3"
}

Marinković, T., Radović, I., Borka, D.,& Mišković, Z. L.. (2015). Probing the Plasmon-Phonon Hybridization in Supported Graphene by Externally Moving Charged Particles. in Plasmonics
Springer Nature., 10(6), 1741-1749.
https://doi.org/10.1007/s11468-015-9993-3

Marinković T, Radović I, Borka D, Mišković ZL. Probing the Plasmon-Phonon Hybridization in Supported Graphene by Externally Moving Charged Particles. in Plasmonics. 2015;10(6):1741-1749.
doi:10.1007/s11468-015-9993-3 .

Marinković, Tijana, Radović, Ivan, Borka, Duško, Mišković, Zoran L., "Probing the Plasmon-Phonon Hybridization in Supported Graphene by Externally Moving Charged Particles" in Plasmonics, 10, no. 6 (2015):1741-1749,
https://doi.org/10.1007/s11468-015-9993-3 . .

TY  - JOUR
AU  - Radović, Ivan
AU  - Borka, Duško
AU  - Mišković, Zoran L.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6090
AB  - We present a simple model for the resonant feature designated as the pi plasmon in single-layer graphene supported by a metal substrate, which is excited via high-resolution electron energy loss spectroscopy (HREELS) in the off-specular scattering geometry. Using a two-dimensional, two-fluid hydrodynamic model for interband transitions of graphenes pi and sigma electrons and an empirical Drude-Lorentz model for the metal in the local approximation enables us to reproduce, at the qualitative and semi-quantitative levels, the typical experimental features of the HREEL spectra in the visible to the ultraviolet frequency range. (C) 2014 Elsevier B.V. All rights reserved.
T2  - Physics Letters A
T1  - Theoretical modeling of experimental HREEL spectra for supported graphene
VL  - 378
IS  - 30-31
SP  - 2206
EP  - 2210
DO  - 10.1016/j.physleta.2014.06.001
ER  - 

@article{
author = "Radović, Ivan and Borka, Duško and Mišković, Zoran L.",
year = "2014",
abstract = "We present a simple model for the resonant feature designated as the pi plasmon in single-layer graphene supported by a metal substrate, which is excited via high-resolution electron energy loss spectroscopy (HREELS) in the off-specular scattering geometry. Using a two-dimensional, two-fluid hydrodynamic model for interband transitions of graphenes pi and sigma electrons and an empirical Drude-Lorentz model for the metal in the local approximation enables us to reproduce, at the qualitative and semi-quantitative levels, the typical experimental features of the HREEL spectra in the visible to the ultraviolet frequency range. (C) 2014 Elsevier B.V. All rights reserved.",
journal = "Physics Letters A",
title = "Theoretical modeling of experimental HREEL spectra for supported graphene",
volume = "378",
number = "30-31",
pages = "2206-2210",
doi = "10.1016/j.physleta.2014.06.001"
}

Radović, I., Borka, D.,& Mišković, Z. L.. (2014). Theoretical modeling of experimental HREEL spectra for supported graphene. in Physics Letters A, 378(30-31), 2206-2210.
https://doi.org/10.1016/j.physleta.2014.06.001

Radović I, Borka D, Mišković ZL. Theoretical modeling of experimental HREEL spectra for supported graphene. in Physics Letters A. 2014;378(30-31):2206-2210.
doi:10.1016/j.physleta.2014.06.001 .

Radović, Ivan, Borka, Duško, Mišković, Zoran L., "Theoretical modeling of experimental HREEL spectra for supported graphene" in Physics Letters A, 378, no. 30-31 (2014):2206-2210,
https://doi.org/10.1016/j.physleta.2014.06.001 . .

TY  - JOUR
AU  - Radović, Ivan
AU  - Borka, Duško
AU  - Mišković, Zoran L.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5707
AB  - We study the wake effect in the charge carrier density in free graphene induced by an electric dipole moving parallel to it by using the dynamic polarization function of graphene within the random phase approximation for its pi electrons described as Diracs fermions. We show that, while the equilibrium doping density of graphene sets a length scale for the period of the wake via graphenes Fermi wavenumber, qualitative properties of the wake are strongly affected by the speed of the dipole, its distance from graphene, and the dipole moment orientation. (C) 2013 Elsevier B.V. All rights reserved.
T2  - Physics Letters A
T1  - Wake effect in interactions of dipolar molecules with doped graphene
VL  - 377
IS  - 38
SP  - 2614
EP  - 2620
DO  - 10.1016/j.physleta.2013.07.038
ER  - 

@article{
author = "Radović, Ivan and Borka, Duško and Mišković, Zoran L.",
year = "2013",
abstract = "We study the wake effect in the charge carrier density in free graphene induced by an electric dipole moving parallel to it by using the dynamic polarization function of graphene within the random phase approximation for its pi electrons described as Diracs fermions. We show that, while the equilibrium doping density of graphene sets a length scale for the period of the wake via graphenes Fermi wavenumber, qualitative properties of the wake are strongly affected by the speed of the dipole, its distance from graphene, and the dipole moment orientation. (C) 2013 Elsevier B.V. All rights reserved.",
journal = "Physics Letters A",
title = "Wake effect in interactions of dipolar molecules with doped graphene",
volume = "377",
number = "38",
pages = "2614-2620",
doi = "10.1016/j.physleta.2013.07.038"
}

Radović, I., Borka, D.,& Mišković, Z. L.. (2013). Wake effect in interactions of dipolar molecules with doped graphene. in Physics Letters A, 377(38), 2614-2620.
https://doi.org/10.1016/j.physleta.2013.07.038

Radović I, Borka D, Mišković ZL. Wake effect in interactions of dipolar molecules with doped graphene. in Physics Letters A. 2013;377(38):2614-2620.
doi:10.1016/j.physleta.2013.07.038 .

Radović, Ivan, Borka, Duško, Mišković, Zoran L., "Wake effect in interactions of dipolar molecules with doped graphene" in Physics Letters A, 377, no. 38 (2013):2614-2620,
https://doi.org/10.1016/j.physleta.2013.07.038 . .

TY  - JOUR
AU  - Radović, Ivan
AU  - Borka, Duško
AU  - Mišković, Zoran L.
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4527
AB  - We use the dielectric-response formalism to evaluate the induced density of charge carriers in supported graphene due to an external moving charged particle in terms of its velocity and distance from graphene for several equilibrium charge carrier densities due to graphene doping. We show that, when the particle speed exceeds a threshold value, an oscillatory wake effect develops in the induced charge density trailing the particle. Strong effects are observed in the wake pattern due to finite size of the graphene-substrate gap, as well as due to strong coupling effects, and plasmon damping of graphenes pi electrons. (C) 2011 Elsevier B.V. All rights reserved.
T2  - Physics Letters A
T1  - Wake effect in doped graphene due to moving external charge
VL  - 375
IS  - 42
SP  - 3720
EP  - 3725
DO  - 10.1016/j.physleta.2011.08.053
ER  - 

@article{
author = "Radović, Ivan and Borka, Duško and Mišković, Zoran L.",
year = "2011",
abstract = "We use the dielectric-response formalism to evaluate the induced density of charge carriers in supported graphene due to an external moving charged particle in terms of its velocity and distance from graphene for several equilibrium charge carrier densities due to graphene doping. We show that, when the particle speed exceeds a threshold value, an oscillatory wake effect develops in the induced charge density trailing the particle. Strong effects are observed in the wake pattern due to finite size of the graphene-substrate gap, as well as due to strong coupling effects, and plasmon damping of graphenes pi electrons. (C) 2011 Elsevier B.V. All rights reserved.",
journal = "Physics Letters A",
title = "Wake effect in doped graphene due to moving external charge",
volume = "375",
number = "42",
pages = "3720-3725",
doi = "10.1016/j.physleta.2011.08.053"
}

Radović, I., Borka, D.,& Mišković, Z. L.. (2011). Wake effect in doped graphene due to moving external charge. in Physics Letters A, 375(42), 3720-3725.
https://doi.org/10.1016/j.physleta.2011.08.053

Radović I, Borka D, Mišković ZL. Wake effect in doped graphene due to moving external charge. in Physics Letters A. 2011;375(42):3720-3725.
doi:10.1016/j.physleta.2011.08.053 .

Radović, Ivan, Borka, Duško, Mišković, Zoran L., "Wake effect in doped graphene due to moving external charge" in Physics Letters A, 375, no. 42 (2011):3720-3725,
https://doi.org/10.1016/j.physleta.2011.08.053 . .

TY  - CONF
AU  - Radović, Ivan
AU  - Borka Jovanović, Vesna
AU  - Mišković, Zoran
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12642
AB  - We use a quantum hydrodynamic (QHD) model to describe the high-frequency plasmon excitations of the carbon valence electrons responding to fast ions which move parallel to a single sheet of graphene supported by an insulating substrate. We calculate the stopping and the image forces on ions. Numerical results are obtained showing the effects of variation in size of the gap between graphene and the SiO2 substrate, as well as the effects of a finite frictional coefficient, on these quantities
C3  - Publications of the Astronomical Observatory of Belgrade
T1  - Interactions of fast ions with supported graphene: Quantum hydrodynamic model
IS  - 89
SP  - 117
EP  - 220
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12642
ER  - 

@conference{
author = "Radović, Ivan and Borka Jovanović, Vesna and Mišković, Zoran",
year = "2010",
abstract = "We use a quantum hydrodynamic (QHD) model to describe the high-frequency plasmon excitations of the carbon valence electrons responding to fast ions which move parallel to a single sheet of graphene supported by an insulating substrate. We calculate the stopping and the image forces on ions. Numerical results are obtained showing the effects of variation in size of the gap between graphene and the SiO2 substrate, as well as the effects of a finite frictional coefficient, on these quantities",
journal = "Publications of the Astronomical Observatory of Belgrade",
title = "Interactions of fast ions with supported graphene: Quantum hydrodynamic model",
number = "89",
pages = "117-220",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12642"
}

Radović, I., Borka Jovanović, V.,& Mišković, Z.. (2010). Interactions of fast ions with supported graphene: Quantum hydrodynamic model. in Publications of the Astronomical Observatory of Belgrade(89), 117-220.
https://hdl.handle.net/21.15107/rcub_vinar_12642

Radović I, Borka Jovanović V, Mišković Z. Interactions of fast ions with supported graphene: Quantum hydrodynamic model. in Publications of the Astronomical Observatory of Belgrade. 2010;(89):117-220.
https://hdl.handle.net/21.15107/rcub_vinar_12642 .

Radović, Ivan, Borka Jovanović, Vesna, Mišković, Zoran, "Interactions of fast ions with supported graphene: Quantum hydrodynamic model" in Publications of the Astronomical Observatory of Belgrade, no. 89 (2010):117-220,
https://hdl.handle.net/21.15107/rcub_vinar_12642 .

TY  - JOUR
AU  - Radović, Ivan
AU  - Hadžievski, Ljupčo
AU  - Bibić, Nataša M.
AU  - Mišković, Zoran L.
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6852
AB  - In this work, we study the interactions of fast ions with graphene describing the excitations of the electron gas in graphene by a two-dimensional (2D) hydrodynamic model (one-fluid and two-fluid model). The two-fluid model reproduces qualitatively the split of plasmon dispersions into the low-frequency pi-electron branch and the high-frequency sigma+pi-electron branch. We calculate the stopping force and the image force on an ion moving parallel to a single sheet of graphene. Numerical results show that the presence of the low-energy, quasiacoustic plasmon in the two-fluid model gives rise to resonant features at low velocities around its acoustic speed, which are not seen in the one-fluid model. The two models give virtually indistinguishable results for both forces at high speeds. Marked differences between the two models in the values of image forces at low speeds can be seen. Numerical results show that the magnitudes of both the stopping and image forces exhibit typical resonance-shaped velocity dependencies, with the peak positions moving to higher velocities for higher distances and with the overall magnitudes decreasing sharply with increasing distances. The second order corrections are found to be small, as expected for fast ions outside the electron gas, but their relative magnitudes should be easily discernible in experiments on ion grazing scattering from graphene. One notices effects which are similar to those obtained earlier for proton channeling in carbon nanotubes.
T2  - Hemijska industrija
T1  - Interactions of Fast Ions with Graphene
VL  - 63
IS  - 3
SP  - 151
EP  - 157
DO  - 10.2298/HEMIND0903151R
ER  - 

@article{
author = "Radović, Ivan and Hadžievski, Ljupčo and Bibić, Nataša M. and Mišković, Zoran L.",
year = "2009",
abstract = "In this work, we study the interactions of fast ions with graphene describing the excitations of the electron gas in graphene by a two-dimensional (2D) hydrodynamic model (one-fluid and two-fluid model). The two-fluid model reproduces qualitatively the split of plasmon dispersions into the low-frequency pi-electron branch and the high-frequency sigma+pi-electron branch. We calculate the stopping force and the image force on an ion moving parallel to a single sheet of graphene. Numerical results show that the presence of the low-energy, quasiacoustic plasmon in the two-fluid model gives rise to resonant features at low velocities around its acoustic speed, which are not seen in the one-fluid model. The two models give virtually indistinguishable results for both forces at high speeds. Marked differences between the two models in the values of image forces at low speeds can be seen. Numerical results show that the magnitudes of both the stopping and image forces exhibit typical resonance-shaped velocity dependencies, with the peak positions moving to higher velocities for higher distances and with the overall magnitudes decreasing sharply with increasing distances. The second order corrections are found to be small, as expected for fast ions outside the electron gas, but their relative magnitudes should be easily discernible in experiments on ion grazing scattering from graphene. One notices effects which are similar to those obtained earlier for proton channeling in carbon nanotubes.",
journal = "Hemijska industrija",
title = "Interactions of Fast Ions with Graphene",
volume = "63",
number = "3",
pages = "151-157",
doi = "10.2298/HEMIND0903151R"
}

Radović, I., Hadžievski, L., Bibić, N. M.,& Mišković, Z. L.. (2009). Interactions of Fast Ions with Graphene. in Hemijska industrija, 63(3), 151-157.
https://doi.org/10.2298/HEMIND0903151R

Radović I, Hadžievski L, Bibić NM, Mišković ZL. Interactions of Fast Ions with Graphene. in Hemijska industrija. 2009;63(3):151-157.
doi:10.2298/HEMIND0903151R .

Radović, Ivan, Hadžievski, Ljupčo, Bibić, Nataša M., Mišković, Zoran L., "Interactions of Fast Ions with Graphene" in Hemijska industrija, 63, no. 3 (2009):151-157,
https://doi.org/10.2298/HEMIND0903151R . .