R. Z. Vitlina

Screening of electron-electron interaction in semiconductor nanotubes

Expressions describing the asymptotic behavior of the screened Coulomb interaction between electrons on the surface of an empty cylinder (a nanotube) are derived. It is shown that the axially symmetric part of the potential experiences a logarithmically weak screening, while the higher harmonics are screened according to the dielectric mechanism.

Amplification of plasma oscillations in an asymmetric double quantum well

It is shown that the subband population inversion in an asymmetric double quantum well can result in the amplification of optical plasma oscillations.

Short-Wavelength Plasmons in Low-Dimensional Systems

The dispersion of plasma waves in systems of various dimensions is investigated up to the end point of the spectrum. In 2D and 3D systems, the plasmon spectrum still ends (due to Landau damping) within the applicability range of the quasi-classical approximation, i.e., for ħk ≪ pF (ħk is the plasmon momentum and pF is the electron Fermi momentum). In 1D systems, the results are qualitatively different, since the Landau damping is concentrated in a region where the quantum effects cannot be ignored. This peculiarity of 1D systems gives rise to undamped branches of acoustic plasmons with a phase velocity lower than the electron Fermi velocity in multicomponent 1D plasmas.

Cyclotron resonance in a two-dimensional semimetal

Cyclotron resonance in a two-dimensional semimetal has been studied theoretically, keeping in mind recent experiments reported in Z. D. Kvon, S. N. Pamilov, S. D. Ganichev, et al., in Proceedings of the 14th International Conference on Narrow Gap Semiconductors and Systems (Sendai, Japan, 2009). Since the size of the sample is finite, the exciting microwave inhomogeneous and there is a plasma shift of resonance frequency. There are two magnetoplasmon branches in a two-component system, which undergo pseudocrossing under the found criterion. Resonance frequencies and intensities of absorption peaks have been found. The latter are complicated functions of the electron and hole densities.

Spin-magnetoplasma waves in a 2D electron system

Oscillations of a 2D electron plasma in a transverse magnetic field have been theoretically studied taking into account spin-orbit interaction. Four branches of spin-plasmon oscillations associated with different selection rules for spin and orbital quantum numbers have been shown to appear at a small plasmon momentum in a semiclassical limit (the Fermi energy is much higher than the Landau quantum). In the quantum case (the filling factor ν is about unity), the number of branches changes from three to six depending on ν value.

On the effect of the Coulomb interaction between electrons on the inelastic scattering of light

The Raman scattering by a donor center in a two-dimensional system has been studied theoretically. It has been shown by the example of a donor in a cubic crystal that the inclusion of the electron–electron interaction regardless of its particular form leads to specific polarization dependences of the resonance scattering cross section.

Inelastic light scattering by a two-dimensional electron system with Rashba spin-orbit coupling

Inelastic light scattering by a two-dimensional system of electrons in a conduction band with Rashba spinorbit coupling is studied theoretically for the resonance case where the frequencies of the incident and scattered light are close to the effective distance between the conduction band and spin-split band in a III–V semiconductor. It is shown that, in contrast to the case of no spin-orbit coupling, the spectrum of the scattered light exhibits a plasmon peak even for strictly perpendicular polarizations of the incident and scattered light. There exists a configuration where the scattering spectrum exhibits features originating from single-particle transitions only. Furthermore, it is shown that, for the general case of elliptic polarizations of the incident and scattered light, the amplitude of the plasmon peak depends on the sign of the effective Rashba spinorbit coupling constant and the signs of the phases of the polarization vectors. This fact can be used to determine the sign of the Rashba constant.

Magnetoplasma oscillations of a two-dimensional electron system with spin-orbit interaction in a lateral superlattice

Low-frequency magnetoplasmon modes in a one-dimensional lateral superlattice with Rashba spin-orbit splitting are considered. Such modes correspond to oscillations related to virtual transitions within a Landau level that become possible due to the broadening of each Landau level into a band produced by the superlattice potential. The specificity of the one-dimensional intersubband plasmons emerging in such a system has been revealed.

Magnetoplasma oscillations in a 2D electron system with spin-orbit interaction

The magnetoplasmon spectrum in a 2D electron plasma is investigated theoretically taking into account the spin—orbit interaction in the Rashba model. The expression is derived for the polarization operator in the semiclassical range of magnetic fields (in which the Fermi energy eF is much larger than the Landau quantum). Approximate analytic formulas are obtained for spin—plasmon branches. The dependences of plasma wave frequencies on the wavevector and magnetic field are calculated from a numerical solution of the dispersion equation. In addition, the magnetic field and frequency dependences of the plasmon absorption intensity are constructed. The absorption intensity at the peak is found to be sensitive to the spin—orbit interaction constant.

Intersubband plasmons in a quasi-one-dimensional system

It has been shown that plasma oscillations in quasi-one-dimensional systems feature the presence of two branches of intersubband plasmons for each pair of subbands. The second (low-frequency) branch lies in the region of the frequency-momentum plane, where a plasma-wave-induced single-particle transition is allowed but there is no Landau damping.