TY  - JOUR
AU  - Tahir, Muhammad
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3974
AB  - The multilayer band structure of black phosphorus (BP) is highly anisotropic, and its bandgap is tunable by applying a perpendicular electric field Ez . Within a linear response theory, we study dc and ac transport in few-layer BP, as functions of the Fermi energy, temperature, or frequency,
in the presence of a Zeeman field. The current response to an in-plane electric field along two perpendicular directions is anisotropic and reflects that of the energy spectrum. In addition, we study the Hall conductivity and power absorption spectrum. The Hall
conductivity vanishes, but the power spectrum P(ω) shows a considerable structure as a function of the normalized frequency α/hω=2Δ and/or of the bandgap 2Δ tuned by Ez. In particular, a clear maximum occurs in the difference between spin-up and spin-down contributions
to P(ω). When potassium (K) atoms are deposited on top of BP, the anisotropy in the current response is stronger and the power spectrum is further modified. The results may be pertinent to the development of phosphorene-based applications.
PB  - American Institute of Physics (AIP Publishing)
T2  - Journal of Applied Physics
T1  - dc and ac transport in few-layer black phosphorus
VL  - 127
SP  - 044302
DO  - 10.1063/1.5129273
ER  - 

@article{
author = "Tahir, Muhammad and Krstajić, Predrag and Vasilopoulos, Panagiotis",
year = "2020",
abstract = "The multilayer band structure of black phosphorus (BP) is highly anisotropic, and its bandgap is tunable by applying a perpendicular electric field Ez . Within a linear response theory, we study dc and ac transport in few-layer BP, as functions of the Fermi energy, temperature, or frequency,
in the presence of a Zeeman field. The current response to an in-plane electric field along two perpendicular directions is anisotropic and reflects that of the energy spectrum. In addition, we study the Hall conductivity and power absorption spectrum. The Hall
conductivity vanishes, but the power spectrum P(ω) shows a considerable structure as a function of the normalized frequency α/hω=2Δ and/or of the bandgap 2Δ tuned by Ez. In particular, a clear maximum occurs in the difference between spin-up and spin-down contributions
to P(ω). When potassium (K) atoms are deposited on top of BP, the anisotropy in the current response is stronger and the power spectrum is further modified. The results may be pertinent to the development of phosphorene-based applications.",
publisher = "American Institute of Physics (AIP Publishing)",
journal = "Journal of Applied Physics",
title = "dc and ac transport in few-layer black phosphorus",
volume = "127",
pages = "044302",
doi = "10.1063/1.5129273"
}

Tahir, M., Krstajić, P.,& Vasilopoulos, P.. (2020). dc and ac transport in few-layer black phosphorus. in Journal of Applied Physics
American Institute of Physics (AIP Publishing)., 127, 044302.
https://doi.org/10.1063/1.5129273

Tahir M, Krstajić P, Vasilopoulos P. dc and ac transport in few-layer black phosphorus. in Journal of Applied Physics. 2020;127:044302.
doi:10.1063/1.5129273 .

Tahir, Muhammad, Krstajić, Predrag, Vasilopoulos, Panagiotis, "dc and ac transport in few-layer black phosphorus" in Journal of Applied Physics, 127 (2020):044302,
https://doi.org/10.1063/1.5129273 . .

TY  - JOUR
AU  - Tahir, Muhammad
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2418
AB  - We investigate quantum transport in a bilayer WSe2 in the presence of an external potential V and interlayer coupling. The dc and ac conductivities are evaluated in the framework of linear response theory. As functions of the Fermi energy, the dc ones exhibit a nonmonotonic behavior with a flat region in the band gap. A deep local minimum is visible in spin-Hall conductivity near the top of the valence band as a consequence of a large valence band splitting. On the other hand, the ac spin- and valley-Hall conductivities, as functions of the frequency, show two opposite peaks near the top of the valence band. The spin-Hall conductivity exhibits a minimum value at V = 0 whereas the valley-Hall conductivity decreases monotonically upon varying V from negative to positive values. Furthermore, we evaluate the power absorption spectrum and assess its dependence on the spin and valley degrees of freedom. The results are pertinent to the development of electrically controlled spintronic and valleytronic devices based on bilayer WSe2 and other group VI semiconductors.
PB  - American Physical Society (APS)
T2  - Physical Review B
T1  - Electrically controlled dc and ac transport in bilayer WSe2
VL  - 98
IS  - 7
SP  - 075429
DO  - 10.1103/PhysRevB.98.075429
ER  - 

@article{
author = "Tahir, Muhammad and Krstajić, Predrag and Vasilopoulos, Panagiotis",
year = "2018",
abstract = "We investigate quantum transport in a bilayer WSe2 in the presence of an external potential V and interlayer coupling. The dc and ac conductivities are evaluated in the framework of linear response theory. As functions of the Fermi energy, the dc ones exhibit a nonmonotonic behavior with a flat region in the band gap. A deep local minimum is visible in spin-Hall conductivity near the top of the valence band as a consequence of a large valence band splitting. On the other hand, the ac spin- and valley-Hall conductivities, as functions of the frequency, show two opposite peaks near the top of the valence band. The spin-Hall conductivity exhibits a minimum value at V = 0 whereas the valley-Hall conductivity decreases monotonically upon varying V from negative to positive values. Furthermore, we evaluate the power absorption spectrum and assess its dependence on the spin and valley degrees of freedom. The results are pertinent to the development of electrically controlled spintronic and valleytronic devices based on bilayer WSe2 and other group VI semiconductors.",
publisher = "American Physical Society (APS)",
journal = "Physical Review B",
title = "Electrically controlled dc and ac transport in bilayer WSe2",
volume = "98",
number = "7",
pages = "075429",
doi = "10.1103/PhysRevB.98.075429"
}

Tahir, M., Krstajić, P.,& Vasilopoulos, P.. (2018). Electrically controlled dc and ac transport in bilayer WSe2. in Physical Review B
American Physical Society (APS)., 98(7), 075429.
https://doi.org/10.1103/PhysRevB.98.075429

Tahir M, Krstajić P, Vasilopoulos P. Electrically controlled dc and ac transport in bilayer WSe2. in Physical Review B. 2018;98(7):075429.
doi:10.1103/PhysRevB.98.075429 .

Tahir, Muhammad, Krstajić, Predrag, Vasilopoulos, Panagiotis, "Electrically controlled dc and ac transport in bilayer WSe2" in Physical Review B, 98, no. 7 (2018):075429,
https://doi.org/10.1103/PhysRevB.98.075429 . .

TY  - JOUR
AU  - Tahir, Muhammad
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2236
AB  - The recent experimental realization of high-quality WSe2 leads to the possibility of an efficient manipulation of its spin and valley degrees of freedom. Its electronic properties comprise a huge spin-orbit coupling, a direct band gap, and a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We evaluate its band structure and study ballistic electron transport through single and double junctions (or barriers) on monolayer WSe2 in the presence of spin M-s and valley M-v Zeeman fields and of an electric potential U. The conductance versus the field Ms or Mv decreases in a fluctuating manner. For a single junction, the spin P-s and valley P-v polarizations rise with M = M-v = 2M(s), reach a value of more than 55%, and become perfect above U approximate to 45 meV while for a double junction this change can occur for U >= 50 meV and M >= 5 meV. In certain regions of the (M, U) plane P-v becomes perfect. The conductance g(c), its spin-up and spin-down components, and both polarizations oscillate with the barrier width d. The ability to isolate various carrier degrees of freedom in WSe2 may render it a promising candidate for new spintronic and valleytronic devices.
PB  - Amer Physical Soc, College Pk
T2  - Physical Review B
T1  - Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2
VL  - 95
IS  - 23
SP  - 235402
DO  - 10.1103/PhysRevB.95.235402
ER  - 

@article{
author = "Tahir, Muhammad and Krstajić, Predrag and Vasilopoulos, Panagiotis",
year = "2017",
abstract = "The recent experimental realization of high-quality WSe2 leads to the possibility of an efficient manipulation of its spin and valley degrees of freedom. Its electronic properties comprise a huge spin-orbit coupling, a direct band gap, and a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We evaluate its band structure and study ballistic electron transport through single and double junctions (or barriers) on monolayer WSe2 in the presence of spin M-s and valley M-v Zeeman fields and of an electric potential U. The conductance versus the field Ms or Mv decreases in a fluctuating manner. For a single junction, the spin P-s and valley P-v polarizations rise with M = M-v = 2M(s), reach a value of more than 55%, and become perfect above U approximate to 45 meV while for a double junction this change can occur for U >= 50 meV and M >= 5 meV. In certain regions of the (M, U) plane P-v becomes perfect. The conductance g(c), its spin-up and spin-down components, and both polarizations oscillate with the barrier width d. The ability to isolate various carrier degrees of freedom in WSe2 may render it a promising candidate for new spintronic and valleytronic devices.",
publisher = "Amer Physical Soc, College Pk",
journal = "Physical Review B",
title = "Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2",
volume = "95",
number = "23",
pages = "235402",
doi = "10.1103/PhysRevB.95.235402"
}

Tahir, M., Krstajić, P.,& Vasilopoulos, P.. (2017). Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2. in Physical Review B
Amer Physical Soc, College Pk., 95(23), 235402.
https://doi.org/10.1103/PhysRevB.95.235402

Tahir M, Krstajić P, Vasilopoulos P. Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2. in Physical Review B. 2017;95(23):235402.
doi:10.1103/PhysRevB.95.235402 .

Tahir, Muhammad, Krstajić, Predrag, Vasilopoulos, Panagiotis, "Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2" in Physical Review B, 95, no. 23 (2017):235402,
https://doi.org/10.1103/PhysRevB.95.235402 . .

TY  - JOUR
AU  - Tahir, Muhammad
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2146
AB  - The electronic properties of WSe2 comprise a huge spin-orbit coupling, a wide direct band gap, and especially a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We study ballistic electron transport through single or double junctions on monolayer WSe2 in the presence of spin M-s and valley M-v Zeeman fields and of an electric potential U. The conductance vs. the field M-s or M-v decreases in a fluctuating manner. For a single junction the spin P-s and valley P-v polarizations rise with M = M-v = 2M(s), reach a value of more than 70%, and become perfect above U approximate to 90meV while for a double junction this change can occur for U approximate to 50meV and M >= 10meV. Pv increases with U and both polarizations oscillate with the junction width. The results may render WSe2 a promising candidate for new spintronic and valleytronic devices.
PB  - Epl Association, European Physical Society, Mulhouse
T2  - Europhysics Letters
T1  - Zeeman- and electric-field control of spin- and valley-polarized transport through biased magnetic junctions on WSe2
VL  - 118
IS  - 1
DO  - 10.1209/0295-5075/118/17001
ER  - 

@article{
author = "Tahir, Muhammad and Krstajić, Predrag and Vasilopoulos, Panagiotis",
year = "2017",
abstract = "The electronic properties of WSe2 comprise a huge spin-orbit coupling, a wide direct band gap, and especially a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We study ballistic electron transport through single or double junctions on monolayer WSe2 in the presence of spin M-s and valley M-v Zeeman fields and of an electric potential U. The conductance vs. the field M-s or M-v decreases in a fluctuating manner. For a single junction the spin P-s and valley P-v polarizations rise with M = M-v = 2M(s), reach a value of more than 70%, and become perfect above U approximate to 90meV while for a double junction this change can occur for U approximate to 50meV and M >= 10meV. Pv increases with U and both polarizations oscillate with the junction width. The results may render WSe2 a promising candidate for new spintronic and valleytronic devices.",
publisher = "Epl Association, European Physical Society, Mulhouse",
journal = "Europhysics Letters",
title = "Zeeman- and electric-field control of spin- and valley-polarized transport through biased magnetic junctions on WSe2",
volume = "118",
number = "1",
doi = "10.1209/0295-5075/118/17001"
}

Tahir, M., Krstajić, P.,& Vasilopoulos, P.. (2017). Zeeman- and electric-field control of spin- and valley-polarized transport through biased magnetic junctions on WSe2. in Europhysics Letters
Epl Association, European Physical Society, Mulhouse., 118(1).
https://doi.org/10.1209/0295-5075/118/17001

Tahir M, Krstajić P, Vasilopoulos P. Zeeman- and electric-field control of spin- and valley-polarized transport through biased magnetic junctions on WSe2. in Europhysics Letters. 2017;118(1).
doi:10.1209/0295-5075/118/17001 .

Tahir, Muhammad, Krstajić, Predrag, Vasilopoulos, Panagiotis, "Zeeman- and electric-field control of spin- and valley-polarized transport through biased magnetic junctions on WSe2" in Europhysics Letters, 118, no. 1 (2017),
https://doi.org/10.1209/0295-5075/118/17001 . .

TY  - JOUR
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
AU  - Tahir, Muhammad
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1842
AB  - We investigate dc and ac transport in a monolayer of MoS2 in the presence of an effective mass asymmetry, a momentum-dependent term, and an out-of plane or in-plane Zeeman term. Analytical results are presented for both dc and ac conductivities in the framework of linear response theory. We show that the spin-Hall conductivity exhibits a strong dependence on the strength of the spin-orbit interaction while both spin-and valley-Hall conductivities show a very weak dependence on the temperature. The sum of the well separated spin-up and spin-down components of the diffusive dc longitudinal conductivity is linear in the electron concentration though the Fermi level is a nonmonotonic function of it. Further, we evaluate the power absorption spectrum and assess its dependence on the spin and valley degrees of freedom as well as on the scattering which is essential at low frequencies.
PB  - Amer Physical Soc, College Pk
T2  - Physical Review B
T1  - Spin- and valley-polarized transport in a monolayer of MoS2
VL  - 94
IS  - 8
SP  - 085413
DO  - 10.1103/PhysRevB.94.085413
ER  - 

@article{
author = "Krstajić, Predrag and Vasilopoulos, Panagiotis and Tahir, Muhammad",
year = "2016",
abstract = "We investigate dc and ac transport in a monolayer of MoS2 in the presence of an effective mass asymmetry, a momentum-dependent term, and an out-of plane or in-plane Zeeman term. Analytical results are presented for both dc and ac conductivities in the framework of linear response theory. We show that the spin-Hall conductivity exhibits a strong dependence on the strength of the spin-orbit interaction while both spin-and valley-Hall conductivities show a very weak dependence on the temperature. The sum of the well separated spin-up and spin-down components of the diffusive dc longitudinal conductivity is linear in the electron concentration though the Fermi level is a nonmonotonic function of it. Further, we evaluate the power absorption spectrum and assess its dependence on the spin and valley degrees of freedom as well as on the scattering which is essential at low frequencies.",
publisher = "Amer Physical Soc, College Pk",
journal = "Physical Review B",
title = "Spin- and valley-polarized transport in a monolayer of MoS2",
volume = "94",
number = "8",
pages = "085413",
doi = "10.1103/PhysRevB.94.085413"
}

Krstajić, P., Vasilopoulos, P.,& Tahir, M.. (2016). Spin- and valley-polarized transport in a monolayer of MoS2. in Physical Review B
Amer Physical Soc, College Pk., 94(8), 085413.
https://doi.org/10.1103/PhysRevB.94.085413

Krstajić P, Vasilopoulos P, Tahir M. Spin- and valley-polarized transport in a monolayer of MoS2. in Physical Review B. 2016;94(8):085413.
doi:10.1103/PhysRevB.94.085413 .

Krstajić, Predrag, Vasilopoulos, Panagiotis, Tahir, Muhammad, "Spin- and valley-polarized transport in a monolayer of MoS2" in Physical Review B, 94, no. 8 (2016):085413,
https://doi.org/10.1103/PhysRevB.94.085413 . .

TY  - JOUR
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
AU  - Tahir, Muhammad
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1985
AB  - We study ballistic electron transport through single or double barriers on monolayer MoS2, of width d, in the presence of a ferromagnetic field Moran antiferromagnetic field F. The total conductance,gc, its spin-up and spin-down components, and the polarization oscillate with d or the distance b between two barriers. The corresponding oscillation periods are different. The conductance g(c) versus M decreases in a fluctuating manner with a steep decline at certain value of M. As a function of M the spin polarization P-s oscillates before it becomes 100% while the valley polarization 13, oscillates and steadily increases.
PB  - Elsevier
T2  - Physica E-Low-Dimensional Systems & Nanostructures
T1  - Spin- and valley-polarized transport through ferromagnetic and antiferromagnetic barriers on monolayer MoS2
VL  - 75
SP  - 317
EP  - 321
DO  - 10.1016/j.physe.2015.10.003
ER  - 

@article{
author = "Krstajić, Predrag and Vasilopoulos, Panagiotis and Tahir, Muhammad",
year = "2016",
abstract = "We study ballistic electron transport through single or double barriers on monolayer MoS2, of width d, in the presence of a ferromagnetic field Moran antiferromagnetic field F. The total conductance,gc, its spin-up and spin-down components, and the polarization oscillate with d or the distance b between two barriers. The corresponding oscillation periods are different. The conductance g(c) versus M decreases in a fluctuating manner with a steep decline at certain value of M. As a function of M the spin polarization P-s oscillates before it becomes 100% while the valley polarization 13, oscillates and steadily increases.",
publisher = "Elsevier",
journal = "Physica E-Low-Dimensional Systems & Nanostructures",
title = "Spin- and valley-polarized transport through ferromagnetic and antiferromagnetic barriers on monolayer MoS2",
volume = "75",
pages = "317-321",
doi = "10.1016/j.physe.2015.10.003"
}

Krstajić, P., Vasilopoulos, P.,& Tahir, M.. (2016). Spin- and valley-polarized transport through ferromagnetic and antiferromagnetic barriers on monolayer MoS2. in Physica E-Low-Dimensional Systems & Nanostructures
Elsevier., 75, 317-321.
https://doi.org/10.1016/j.physe.2015.10.003

Krstajić P, Vasilopoulos P, Tahir M. Spin- and valley-polarized transport through ferromagnetic and antiferromagnetic barriers on monolayer MoS2. in Physica E-Low-Dimensional Systems & Nanostructures. 2016;75:317-321.
doi:10.1016/j.physe.2015.10.003 .

Krstajić, Predrag, Vasilopoulos, Panagiotis, Tahir, Muhammad, "Spin- and valley-polarized transport through ferromagnetic and antiferromagnetic barriers on monolayer MoS2" in Physica E-Low-Dimensional Systems & Nanostructures, 75 (2016):317-321,
https://doi.org/10.1016/j.physe.2015.10.003 . .

TY  - JOUR
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1131
AB  - Analytical expressions for the Hall conductivity sigma(yx) and the longitudinal resistivity rho(xx) are derived in gapped, single-layer graphene using linear response theory. The gap 2 Delta, described by a mass term, is induced by a substrate made of hexagonal boron nitride (h-BN) and produces two levels at +/-Delta. It is shown that syx has the same form as for a graphene sample supported by a common substrate without a mass term. The differences are a shift in the energy spectrum, which is not symmetric with respect to the Dirac point for either valley due to the gap, the absence of a zero-energy Landau level, and the nonequivalence of the K and K' valleys. In addition, the dispersion of the energy levels, caused by electron scattering by impurities, modifies mostly plateaus due to the levels at +/-Delta. It is shown that the resistivity rho(xx) exhibits an oscillatory dependence on the electron concentration. The main difference with the usual graphene samples, on SiO2 substrates, occurs near zero concentration, as the energy spectra differ mostly near the Dirac point.
PB  - Amer Physical Soc, College Pk
T2  - Physical Review B
T1  - Integer quantum Hall effect in gapped single-layer graphene
VL  - 86
IS  - 11
SP  - 115432
DO  - 10.1103/PhysRevB.86.115432
ER  - 

@article{
author = "Krstajić, Predrag and Vasilopoulos, Panagiotis",
year = "2012",
abstract = "Analytical expressions for the Hall conductivity sigma(yx) and the longitudinal resistivity rho(xx) are derived in gapped, single-layer graphene using linear response theory. The gap 2 Delta, described by a mass term, is induced by a substrate made of hexagonal boron nitride (h-BN) and produces two levels at +/-Delta. It is shown that syx has the same form as for a graphene sample supported by a common substrate without a mass term. The differences are a shift in the energy spectrum, which is not symmetric with respect to the Dirac point for either valley due to the gap, the absence of a zero-energy Landau level, and the nonequivalence of the K and K' valleys. In addition, the dispersion of the energy levels, caused by electron scattering by impurities, modifies mostly plateaus due to the levels at +/-Delta. It is shown that the resistivity rho(xx) exhibits an oscillatory dependence on the electron concentration. The main difference with the usual graphene samples, on SiO2 substrates, occurs near zero concentration, as the energy spectra differ mostly near the Dirac point.",
publisher = "Amer Physical Soc, College Pk",
journal = "Physical Review B",
title = "Integer quantum Hall effect in gapped single-layer graphene",
volume = "86",
number = "11",
pages = "115432",
doi = "10.1103/PhysRevB.86.115432"
}

Krstajić, P.,& Vasilopoulos, P.. (2012). Integer quantum Hall effect in gapped single-layer graphene. in Physical Review B
Amer Physical Soc, College Pk., 86(11), 115432.
https://doi.org/10.1103/PhysRevB.86.115432

Krstajić P, Vasilopoulos P. Integer quantum Hall effect in gapped single-layer graphene. in Physical Review B. 2012;86(11):115432.
doi:10.1103/PhysRevB.86.115432 .

Krstajić, Predrag, Vasilopoulos, Panagiotis, "Integer quantum Hall effect in gapped single-layer graphene" in Physical Review B, 86, no. 11 (2012):115432,
https://doi.org/10.1103/PhysRevB.86.115432 . .

TY  - JOUR
AU  - Krstajić, Predrag
AU  - Vasilopoulos, Panagiotis
PY  - 2011
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/905
AB  - We investigate the electronic properties of graphene nanostructures when the Fermi velocity and the electrostatic potential vary in space. First, we consider the transmission T and conductance G through single and double barriers. We show that G for velocity barriers differs markedly from that for potential barriers for energies below the height of the latter and it exhibits periodic oscillations as a function of the energy for strong velocity modulation. Special attention is given to superlattices (SLs). It is shown that an applied bias can efficiently widen or shrink the allowed minibands of velocity-modulated SLs. The spectrum in the Kronig-Penney limit is periodic in the strength of the barriers. Collimation of an electron beam incident on an SL with velocity and potential barriers is present but it disappears when the potential barriers are absent. The number of additional Dirac points may change considerably if barriers and wells have sufficiently different Fermi velocities.
PB  - Iop Publishing Ltd, Bristol
T2  - Journal of Physics-Condensed Matter
T1  - Ballistic transport through graphene nanostructures of velocity and potential barriers
VL  - 23
IS  - 13
DO  - 10.1088/0953-8984/23/13/135302
ER  - 

@article{
author = "Krstajić, Predrag and Vasilopoulos, Panagiotis",
year = "2011",
abstract = "We investigate the electronic properties of graphene nanostructures when the Fermi velocity and the electrostatic potential vary in space. First, we consider the transmission T and conductance G through single and double barriers. We show that G for velocity barriers differs markedly from that for potential barriers for energies below the height of the latter and it exhibits periodic oscillations as a function of the energy for strong velocity modulation. Special attention is given to superlattices (SLs). It is shown that an applied bias can efficiently widen or shrink the allowed minibands of velocity-modulated SLs. The spectrum in the Kronig-Penney limit is periodic in the strength of the barriers. Collimation of an electron beam incident on an SL with velocity and potential barriers is present but it disappears when the potential barriers are absent. The number of additional Dirac points may change considerably if barriers and wells have sufficiently different Fermi velocities.",
publisher = "Iop Publishing Ltd, Bristol",
journal = "Journal of Physics-Condensed Matter",
title = "Ballistic transport through graphene nanostructures of velocity and potential barriers",
volume = "23",
number = "13",
doi = "10.1088/0953-8984/23/13/135302"
}

Krstajić, P.,& Vasilopoulos, P.. (2011). Ballistic transport through graphene nanostructures of velocity and potential barriers. in Journal of Physics-Condensed Matter
Iop Publishing Ltd, Bristol., 23(13).
https://doi.org/10.1088/0953-8984/23/13/135302

Krstajić P, Vasilopoulos P. Ballistic transport through graphene nanostructures of velocity and potential barriers. in Journal of Physics-Condensed Matter. 2011;23(13).
doi:10.1088/0953-8984/23/13/135302 .

Krstajić, Predrag, Vasilopoulos, Panagiotis, "Ballistic transport through graphene nanostructures of velocity and potential barriers" in Journal of Physics-Condensed Matter, 23, no. 13 (2011),
https://doi.org/10.1088/0953-8984/23/13/135302 . .