arXiv subjects

Oleg G. Balev

Publications and source records attributed to Oleg G. Balev.

4 recordsLinked to original sources

arXiv2018

Self-consistent one-dimensional electron system on liquid helium suspended over a nanoscale dielectric substrate

For electrons above a superfluid helium film suspended on a specially designed dielectric substrate, $z=h(y)$, we obtain that both the transverse, along $z$, and the lateral, along $y$, quantizations are strongly enhanced due to a strong mutual coupling. The self-consistent quantum wires (QWs) with non-degenerated one-dimensional electron systems (1DESs) are obtained over a superfluid liquid helium (LH) suspended self-consistently on different dielectric substrates with a nanoscale modulation. A gap $\gtrsim 10$meV ($\gtrsim 1$meV) is obtained between the lowest two electron levels due to mainly the transverse (lateral) quantization. Our analytical model takes into account a strong interplay between the transverse and the lateral quantizations of an electron. It uses that the characteristic length (energy) along the former direction is essentially smaller (larger) than the one along the latter, in a close analogy with the adiabatic approximation.

cond-mat.mes-hall↗

arXiv2016

Spatial dispersion of magnetic-edge magnetoplasmons: Effect of semi-infinite gate

Magnetic-edge magnetoplasmons (MEMPs) are obtained for a two-dimensional electron system (2DES) with atop semi-infinite metallic gate, at a distance $d$, and atop semi-infinite ferromagnetic film at a strong perpendicular magnetic field. For two most fast MEMPs, one with positive chirality and other with negative chirality, a strong spatial dispersion, due to effect of metallic half-plane gate, is obtained; some slower MEMPs manifest spatial dispersion too. Present MEMPs are localized at the magnetic-edge that is close to the wedge of metallic half-plane gate; the metallic wedge enhances localization of MEMPs at magnetic-edge. Obtained spatial dispersion has unconventional form. In particular, for two most fast MEMPs the phase velocities, $ω/k_{x}$, are the linear polynomials on the wave vector $k_{x}$ in the long-wavelength region, $k_{x}d \ll 1$. Strong effect of the ferromagnetic film hysteresis on the MEMPs phase velocities and their anti-crossings are obtained for $0<k_{x}d \leq1$. Two MEMPs of opposite chirality, especially two most fast MEMPs, at some resonance frequency can create a resonance circuit, with closed wave path along a fraction of the magnetic edge perimeter, with a total change of the wave phase given by an integer of $2π$.

cond-mat.mes-hall↗

arXiv2010

Helical edge magnetoplasmon in the quantum Hall effect regime

We present the microscopic treatment of edge magnetoplasmons (EMPs) for the regime of not-too-low temperatures defined by the condition $\hbar ω_{c}\gg k_{B}T\gg \hbar v_{g}/2\ell_{0}$, where $v_{g}$ is the group velocity of the edge states, $\ell_{0}=\sqrt{\hbar /m^{\ast}ω_{c}}$ is the magnetic length and $ω_{c}$ is the cyclotron frequency. We find a weakly damped symmetric mode, named helical edge magnetoplasmon, which is localized at the edge states region for filling factors $ν=1, 2$ and \textit{very strong dissipation} $η_{T}=ξ/k_{x}\ell_{T}\agt\ln (1/k_{x}\ell_{T})\gg 1$, where the characteristic length $\ell_{T}=k_{B}T\ell_{0}^{2}/\hbar v_{g}\gg \ell_{0}/2$ with $ξ$ being the ratio of the local transverse conductivity to the local Hall conductivity at the edge states and $k_{x}$ is the wave vector along the edge; here other EMP modes are strongly damped. The spatial structure of the helical edge magnetoplasmon, transverse to the edge, is strongly modified as the wave propagates along the edge. In the regime of \textit{weak dissipation}, $η_{T}\ll 1$, we obtain exactly the damping of the fundamental mode as a function of $k_{x}$. For $ν=4$ and weak dissipation we find that the fundamental modes of $n=0$ and $n=1$ Landau levels (LLs) are strongly renormalized due to the Coulomb coupling. Renormalization of all these EMPs coming from a metal gate and air half-space is studied.

cond-mat.mes-hall↗

arXiv2010

Hot carriers in a bipolar graphene

Hot carriers in a doped graphene under dc electric field is described taking into account the intraband energy relaxation due to acoustic phonon scattering and the interband generation-recombination transitions caused by thermal radiation. The consideration is performed for the case when the intercarrier scattering effectively establishes the quasiequilibrium electron-hole distributions, with effective temperature and concentrations of carriers. The concentration and energy balance equations are solved taking into account an interplay between weak energy relaxation and generation-recombination processes. The nonlinear conductivity is calculated for the momentum relaxation caused by the elastic scattering. The current-voltage characteristics, and the transition between bipolar and monopolar regimes of conductivity are obtained and analyzed, for different temperatures and gate voltages.

cond-mat.mes-hall↗