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  - JOUR
AU  - Despoja, Vito
AU  - Radović, Ivan
AU  - Karbunar, Lazar
AU  - Kalinić, Ana
AU  - Mišković, Zoran L.
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8595
AB  - We study the wake potential produced by an external charged particle that moves parallel to various sy1-Al2O3-sy2 sandwich-like composites, where the system syi (with i=1,2) may be vacuum, pristine graphene, or doped graphene. The effective dielectric function of the composites is obtained using three complementary methods for graphene's electronic response, based on the massless Dirac fermions (MDF) method, the extended hydrodynamic (eHD) model, and the ab initio approach. Three velocity regimes are explored with respect to the threshold for excitations of the Dirac plasmon in graphene, given by its Fermi velocity vF. In the low-velocity regime (below vF), only the transverse optical (TO) phonons in the Al2O3 layer contribute to the wake potential in the surface with sy2 (which is nearest to the charged particle), in a manner that is only sensitive to the composition of that system: if sy2 is vacuum, the TO phonons give rise to intense oscillations in the wake potential, which are strongly suppressed if sy2 is pristine or doped graphene. For intermediate velocities (above vF), the hybridized plasmon-TO phonon modes on both surfaces contribute to the wake potential in the surface with sy2, with the most dominant contribution coming from the hybridized Dirac-like plasmonic modes. In the high-velocity regime (well above vF), the highest-lying hybridized Dirac plasmon gives the dominant contribution to the wake potential, which exhibits a typical V-shaped wave-front pattern that lags behind the charged particle. It is found that the MDF method agrees very well with the results of the ab initio method for small and intermediate velocities. However, in the high-velocity regime, the high-energy π plasmon in graphene introduces new features in the wake potential in the form of fast oscillations, just behind the charged particle. Those oscillations in the wake potential are well described by both the eHD and the ab initio method, proving that the π plasmon indeed behaves as a collective mode.
T2  - Physical Review B
T1  - Wake potential in graphene-insulator-graphene composite systems
VL  - 100
IS  - 3
SP  - 035443
DO  - 10.1103/PhysRevB.100.035443
ER  - 

@article{
author = "Despoja, Vito and Radović, Ivan and Karbunar, Lazar and Kalinić, Ana and Mišković, Zoran L.",
year = "2019",
abstract = "We study the wake potential produced by an external charged particle that moves parallel to various sy1-Al2O3-sy2 sandwich-like composites, where the system syi (with i=1,2) may be vacuum, pristine graphene, or doped graphene. The effective dielectric function of the composites is obtained using three complementary methods for graphene's electronic response, based on the massless Dirac fermions (MDF) method, the extended hydrodynamic (eHD) model, and the ab initio approach. Three velocity regimes are explored with respect to the threshold for excitations of the Dirac plasmon in graphene, given by its Fermi velocity vF. In the low-velocity regime (below vF), only the transverse optical (TO) phonons in the Al2O3 layer contribute to the wake potential in the surface with sy2 (which is nearest to the charged particle), in a manner that is only sensitive to the composition of that system: if sy2 is vacuum, the TO phonons give rise to intense oscillations in the wake potential, which are strongly suppressed if sy2 is pristine or doped graphene. For intermediate velocities (above vF), the hybridized plasmon-TO phonon modes on both surfaces contribute to the wake potential in the surface with sy2, with the most dominant contribution coming from the hybridized Dirac-like plasmonic modes. In the high-velocity regime (well above vF), the highest-lying hybridized Dirac plasmon gives the dominant contribution to the wake potential, which exhibits a typical V-shaped wave-front pattern that lags behind the charged particle. It is found that the MDF method agrees very well with the results of the ab initio method for small and intermediate velocities. However, in the high-velocity regime, the high-energy π plasmon in graphene introduces new features in the wake potential in the form of fast oscillations, just behind the charged particle. Those oscillations in the wake potential are well described by both the eHD and the ab initio method, proving that the π plasmon indeed behaves as a collective mode.",
journal = "Physical Review B",
title = "Wake potential in graphene-insulator-graphene composite systems",
volume = "100",
number = "3",
pages = "035443",
doi = "10.1103/PhysRevB.100.035443"
}

Despoja, V., Radović, I., Karbunar, L., Kalinić, A.,& Mišković, Z. L.. (2019). Wake potential in graphene-insulator-graphene composite systems. in Physical Review B, 100(3), 035443.
https://doi.org/10.1103/PhysRevB.100.035443

Despoja V, Radović I, Karbunar L, Kalinić A, Mišković ZL. Wake potential in graphene-insulator-graphene composite systems. in Physical Review B. 2019;100(3):035443.
doi:10.1103/PhysRevB.100.035443 .

Despoja, Vito, Radović, Ivan, Karbunar, Lazar, Kalinić, Ana, Mišković, Zoran L., "Wake potential in graphene-insulator-graphene composite systems" in Physical Review B, 100, no. 3 (2019):035443,
https://doi.org/10.1103/PhysRevB.100.035443 . .