TY  - JOUR
AU  - Kalinić, Ana
AU  - Radović, Ivan
AU  - Karbunar, Lazar
AU  - Despoja, Vito
AU  - Mišković, Zoran L.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11685
AB  - We study the wake effect in a graphene-Al2O3-graphene composite system induced by an external charged particle moving parallel to it by using the dynamic polarization function of graphene within the random phase approximation for its π electrons described as Dirac's fermions and by using a local dielectric function for the bulk sapphire (aluminum oxide, Al2O3). We explore the effects of variation of the particle speed, its distance from the top graphene layer, the thickness of the Al2O3 layer, the damping rate of plasmons in graphene, and the doping density (i.e., Fermi energy) of graphene on the wake potential. For the velocity of the charged particle below the threshold for excitations of the Dirac plasmon in graphene, given by its Fermi velocity , strong effects are observed due to variation of the particle distance, while for the velocity of the charged particle above strong effects are observed due to varying the thickness of the Al2O3 layer, as well as due to plasmon damping of graphene's π electrons, and graphene doping.
T2  - Physica E: Low-dimensional Systems and Nanostructures
T1  - Wake effect in interactions of ions with graphene-sapphire-graphene composite system
VL  - 126
SP  - 114447
DO  - 10.1016/j.physe.2020.114447
ER  - 

@article{
author = "Kalinić, Ana and Radović, Ivan and Karbunar, Lazar and Despoja, Vito and Mišković, Zoran L.",
year = "2021",
abstract = "We study the wake effect in a graphene-Al2O3-graphene composite system induced by an external charged particle moving parallel to it by using the dynamic polarization function of graphene within the random phase approximation for its π electrons described as Dirac's fermions and by using a local dielectric function for the bulk sapphire (aluminum oxide, Al2O3). We explore the effects of variation of the particle speed, its distance from the top graphene layer, the thickness of the Al2O3 layer, the damping rate of plasmons in graphene, and the doping density (i.e., Fermi energy) of graphene on the wake potential. For the velocity of the charged particle below the threshold for excitations of the Dirac plasmon in graphene, given by its Fermi velocity , strong effects are observed due to variation of the particle distance, while for the velocity of the charged particle above strong effects are observed due to varying the thickness of the Al2O3 layer, as well as due to plasmon damping of graphene's π electrons, and graphene doping.",
journal = "Physica E: Low-dimensional Systems and Nanostructures",
title = "Wake effect in interactions of ions with graphene-sapphire-graphene composite system",
volume = "126",
pages = "114447",
doi = "10.1016/j.physe.2020.114447"
}

Kalinić, A., Radović, I., Karbunar, L., Despoja, V.,& Mišković, Z. L.. (2021). Wake effect in interactions of ions with graphene-sapphire-graphene composite system. in Physica E: Low-dimensional Systems and Nanostructures, 126, 114447.
https://doi.org/10.1016/j.physe.2020.114447

Kalinić A, Radović I, Karbunar L, Despoja V, Mišković ZL. Wake effect in interactions of ions with graphene-sapphire-graphene composite system. in Physica E: Low-dimensional Systems and Nanostructures. 2021;126:114447.
doi:10.1016/j.physe.2020.114447 .

Kalinić, Ana, Radović, Ivan, Karbunar, Lazar, Despoja, Vito, Mišković, Zoran L., "Wake effect in interactions of ions with graphene-sapphire-graphene composite system" in Physica E: Low-dimensional Systems and Nanostructures, 126 (2021):114447,
https://doi.org/10.1016/j.physe.2020.114447 . .

TY  - JOUR
AU  - Despoja, Vito
AU  - Radović, Ivan
AU  - Politano, Antonio
AU  - Mišković, Zoran L.
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8953
AB  - The excitation spectrum in the region of the intraband (Dirac plasmon) and interband ( π plasmon) plasmons in graphene/Pt-skin terminated Pt 3 Ni(111) is reproduced by using an ab-initio method and an empirical model. The results of both methods are compared with experimental data. We discover that metallic screening by the Pt layer converts the square-root dispersion of the Dirac plasmon into a linear acoustic-like plasmon dispersion. In the long-wavelength limit, the Pt d electron excitations completely quench the π plasmon in graphene at about 4.1 eV, that is replaced by a broad peak at about 6 eV. Owing to a rather large graphene/Pt-skin separation (≈3.3 Å), the graphene/Pt-skin hybridization becomes weak at larger wave vectors, so that the π plasmon is recovered with a dispersion as in a free-standing graphene.
T2  - Nanomaterials
T1  - Insights on the Excitation Spectrum of Graphene Contacted with a Pt Skin
VL  - 10
IS  - 4
SP  - 703
DO  - 10.3390/nano10040703
ER  - 

@article{
author = "Despoja, Vito and Radović, Ivan and Politano, Antonio and Mišković, Zoran L.",
year = "2020",
abstract = "The excitation spectrum in the region of the intraband (Dirac plasmon) and interband ( π plasmon) plasmons in graphene/Pt-skin terminated Pt 3 Ni(111) is reproduced by using an ab-initio method and an empirical model. The results of both methods are compared with experimental data. We discover that metallic screening by the Pt layer converts the square-root dispersion of the Dirac plasmon into a linear acoustic-like plasmon dispersion. In the long-wavelength limit, the Pt d electron excitations completely quench the π plasmon in graphene at about 4.1 eV, that is replaced by a broad peak at about 6 eV. Owing to a rather large graphene/Pt-skin separation (≈3.3 Å), the graphene/Pt-skin hybridization becomes weak at larger wave vectors, so that the π plasmon is recovered with a dispersion as in a free-standing graphene.",
journal = "Nanomaterials",
title = "Insights on the Excitation Spectrum of Graphene Contacted with a Pt Skin",
volume = "10",
number = "4",
pages = "703",
doi = "10.3390/nano10040703"
}

Despoja, V., Radović, I., Politano, A.,& Mišković, Z. L.. (2020). Insights on the Excitation Spectrum of Graphene Contacted with a Pt Skin. in Nanomaterials, 10(4), 703.
https://doi.org/10.3390/nano10040703

Despoja V, Radović I, Politano A, Mišković ZL. Insights on the Excitation Spectrum of Graphene Contacted with a Pt Skin. in Nanomaterials. 2020;10(4):703.
doi:10.3390/nano10040703 .

Despoja, Vito, Radović, Ivan, Politano, Antonio, Mišković, Zoran L., "Insights on the Excitation Spectrum of Graphene Contacted with a Pt Skin" in Nanomaterials, 10, no. 4 (2020):703,
https://doi.org/10.3390/nano10040703 . .

TY  - CONF
AU  - Radović, Ivan
AU  - Despoja, Vito
AU  - Karbunar, Lazar
AU  - Mišković, Zoran
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12707
AB  - We study the wake effect induced by an external charged particle which moves above various sy1-Al2O3-sy2 composites, where syi (i=1,2) may be vacuum, pristine (undoped) or doped graphene. The polarization functions of graphene sheets are obtained using two approaches within the random phase approximation [1]: an ab initio method and a method based on the massless Dirac fermion approximation. The dynamic response of the layer of Al2O3 (sapphire) is described by a dielectric function consisting of several Lorentzian terms [1]. We evaluate the total electrostatic potential in the plane of the upper graphene sheet (the wake potential). It is shown that in the low velocity limit (below a velocity threshold for the wake given by the Fermi speed of graphene) the charged particle excites only the transverse optical (TO) phonons in the Al2O3 slab and only those phonons contribute to the wake potential. It is also shown that the wake potential is only sensitive on the upper system sy2 such that if sy2 is vacuum then TO phonons give intensive oscillations which are strongly reduced if sy2 is graphene.
C3  - COST Action CA15107 meeting : Multicomp Multi-Functional Nano-Carbon Composite Materials Network : Aveiro Spring Meeting : Book of abstracts
T1  - Wake potential in a graphene-sapphire-graphene structure
SP  - 79
EP  - 79
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12707
ER  - 

@conference{
author = "Radović, Ivan and Despoja, Vito and Karbunar, Lazar and Mišković, Zoran",
year = "2019",
abstract = "We study the wake effect induced by an external charged particle which moves above various sy1-Al2O3-sy2 composites, where syi (i=1,2) may be vacuum, pristine (undoped) or doped graphene. The polarization functions of graphene sheets are obtained using two approaches within the random phase approximation [1]: an ab initio method and a method based on the massless Dirac fermion approximation. The dynamic response of the layer of Al2O3 (sapphire) is described by a dielectric function consisting of several Lorentzian terms [1]. We evaluate the total electrostatic potential in the plane of the upper graphene sheet (the wake potential). It is shown that in the low velocity limit (below a velocity threshold for the wake given by the Fermi speed of graphene) the charged particle excites only the transverse optical (TO) phonons in the Al2O3 slab and only those phonons contribute to the wake potential. It is also shown that the wake potential is only sensitive on the upper system sy2 such that if sy2 is vacuum then TO phonons give intensive oscillations which are strongly reduced if sy2 is graphene.",
journal = "COST Action CA15107 meeting : Multicomp Multi-Functional Nano-Carbon Composite Materials Network : Aveiro Spring Meeting : Book of abstracts",
title = "Wake potential in a graphene-sapphire-graphene structure",
pages = "79-79",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12707"
}

Radović, I., Despoja, V., Karbunar, L.,& Mišković, Z.. (2019). Wake potential in a graphene-sapphire-graphene structure. in COST Action CA15107 meeting : Multicomp Multi-Functional Nano-Carbon Composite Materials Network : Aveiro Spring Meeting : Book of abstracts, 79-79.
https://hdl.handle.net/21.15107/rcub_vinar_12707

Radović I, Despoja V, Karbunar L, Mišković Z. Wake potential in a graphene-sapphire-graphene structure. in COST Action CA15107 meeting : Multicomp Multi-Functional Nano-Carbon Composite Materials Network : Aveiro Spring Meeting : Book of abstracts. 2019;:79-79.
https://hdl.handle.net/21.15107/rcub_vinar_12707 .

Radović, Ivan, Despoja, Vito, Karbunar, Lazar, Mišković, Zoran, "Wake potential in a graphene-sapphire-graphene structure" in COST Action CA15107 meeting : Multicomp Multi-Functional Nano-Carbon Composite Materials Network : Aveiro Spring Meeting : Book of abstracts (2019):79-79,
https://hdl.handle.net/21.15107/rcub_vinar_12707 .

TY  - CONF
AU  - Despoja, Vito
AU  - Radović, Ivan
AU  - Karbunar, Lazar
AU  - Mišković, Zoran
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12665
AB  - We study the wake effect due to excitation of a plasmon-phonon hybrid mode in a sandwich-like structure consisting of two doped graphene sheets, separated by a layer of Al2O3 (sapphire), which is induced by an external charged particle moving parallel to the structure.
PB  - University of Belgrade : Faculty of Physics
C3  - SPIG 2018 : 29th Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers & abstracts of invited lectures, topical invited lectures, progress reports and workshop lectures
T1  - Wake effect due to excitation of plasmon-phonon hybrid modes in a graphene-sapphire-graphene structure by a moving charge
SP  - 82
EP  - 85
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12665
ER  - 

@conference{
author = "Despoja, Vito and Radović, Ivan and Karbunar, Lazar and Mišković, Zoran",
year = "2018",
abstract = "We study the wake effect due to excitation of a plasmon-phonon hybrid mode in a sandwich-like structure consisting of two doped graphene sheets, separated by a layer of Al2O3 (sapphire), which is induced by an external charged particle moving parallel to the structure.",
publisher = "University of Belgrade : Faculty of Physics",
journal = "SPIG 2018 : 29th Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers & abstracts of invited lectures, topical invited lectures, progress reports and workshop lectures",
title = "Wake effect due to excitation of plasmon-phonon hybrid modes in a graphene-sapphire-graphene structure by a moving charge",
pages = "82-85",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12665"
}

Despoja, V., Radović, I., Karbunar, L.,& Mišković, Z.. (2018). Wake effect due to excitation of plasmon-phonon hybrid modes in a graphene-sapphire-graphene structure by a moving charge. in SPIG 2018 : 29th Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers & abstracts of invited lectures, topical invited lectures, progress reports and workshop lectures
University of Belgrade : Faculty of Physics., 82-85.
https://hdl.handle.net/21.15107/rcub_vinar_12665

Despoja V, Radović I, Karbunar L, Mišković Z. Wake effect due to excitation of plasmon-phonon hybrid modes in a graphene-sapphire-graphene structure by a moving charge. in SPIG 2018 : 29th Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers & abstracts of invited lectures, topical invited lectures, progress reports and workshop lectures. 2018;:82-85.
https://hdl.handle.net/21.15107/rcub_vinar_12665 .

Despoja, Vito, Radović, Ivan, Karbunar, Lazar, Mišković, Zoran, "Wake effect due to excitation of plasmon-phonon hybrid modes in a graphene-sapphire-graphene structure by a moving charge" in SPIG 2018 : 29th Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers & abstracts of invited lectures, topical invited lectures, progress reports and workshop lectures (2018):82-85,
https://hdl.handle.net/21.15107/rcub_vinar_12665 .

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 . .