Sviatoslav S. Sokolov

Surface Electron Transport over a Helium Film

The mobility of surface electrons trapped over helium films covering solid substrates is calculated within the Boltzmann kinetic approach. It is shown that the electron mobility is dominated by the roughness scattering of the interface liquid helium-substrate. The mobility dependences on temperature and film thickness are determined and compared with available experimental data. The characteristic values for surface defect sizes of the substrate are in the mesoscopic scale.

Polaronic and Confinement Effects for Surface Electrons on Helium

Surface electrons (SE) on liquid helium constitute an intriguing system which has shown many interesting properties and has led to important theoretical progress in the field of low-dimensionality physics and areas such as phase transitions, many-body theory, transport phenomena, polaron theory, among others. Furthermore, SE have been used in general as a sensitive probe for investigating surface phenomena of quantum liquids, as discussed by Leiderer (1992). There has been a close interplay over the years between theory and experiment in order to predict and elucidate interesting features of this fascinating system.

Plasma Modes of Low-Dimensional Electron Systems over a Helium Film

The dispersion laws for collective modes in low-dimensional electron systems over a superfluid helium film covering a metal substrate are evaluated within the many-body multisubband formalism. In contrast to the electron system over bulk helium, the longitudinal mode is acoustic-like. The transversal mode is optical-like with a gap given by the one-electron spectroscopic intersubband frequency. We found that the effect of depolarization shift is supressed in the quasi-two-dimensional system.

MOBILITY OF SURFACE ELECTRONS OVER THE 3HE-4HE MICROSTRATIFIED SOLUTION

Abstract We have calculated the ripplon-limited mobility of electrons localized over the 3He–4He solution, whose surface contains a thin film enriched with 3He, by taking into account viscous damping in the evaluation of the dispersion relation of interfacial modes. We have considered the electron–ripplon scattering from the low-damped capillary-like mode, which is similar to that of ripplons in uniform liquid. The temperature dependence of the electron mobility is shown for some values of the film thickness. The mobility is also calculated for electrons over pure bulk 3He and an excellent agreement is found with the experimental results.

Chemical potential of the low-dimensional multisubband Fermi gas

In this paper, the chemical potential of two-dimensional (2D) and quasi-one-dimensional (Q1D) multisubband charged Fermi gases is evaluated. We start with a rather general formula for the thermodynamic potential of an ideal quantum statistical system with arbitrary occupation-number to calculate, as a particular case, the chemical potential of the multisubband 2D Fermi gas described by a quadratic energy spectrum. The chemical potential is also studied in the case of a low-dimensional Fermi gas in the presence of a quantizing magnetic field. The same approach is used to study the chemical potential of a multisubband Q1D Fermi gas. The influence of temperature is considered. We found interesting analytical results for special limits as well as numerical results that may be important for the description of both the thermodynamic and kinetic properties of Fermi systems in low dimensionality.

Raman probing of the wave function of collective excitations in the presence of disorder

Abstract The spatial extents of the wave functions of the collective plasmon–LO phonon excitations were studied as a function of the doping concentration and the temperature in the AlGaAs alloy. A strong increase of the localization length was found with the increase of doping, while a decrease of the localization length was detected with the increase of the doping level at higher electron densities. A theoretical analysis based on the variational principle showed that the ionized impurities are responsible for the observed decrease of the localization length.