Volume 32, Issue 1, January 2006
Index of content:
- LOW-DIMENSIONAL AND DISORDERED SYSTEMS
Features of the Shubnikov–de Haas oscillations of the conductivity of a high-mobility two-dimensional hole gas in a quantum well32(2006); http://dx.doi.org/10.1063/1.2161933View Description Hide Description
The Shubnikov–de Haas oscillations in a two-dimensional hole gas in a quantum well of pure germanium in a heterostructure with a hole concentration and mobility are investigated in magnetic fields up to 15 T at temperatures from 40 mK to 4 K. The observed deviation from the known relation describing the conductivity oscillations in the Shubnikov–de Haas effect are explained by additional broadening of the Landau levels due to the existence of a nonuniform distribution of the concentration of charge carriers, and, accordingly, of their energy, in the plane of the two-dimensional gas. It is assumed that the latter is due to natural atomic-step variations of the well width. The effective hole mass is determined from the temperature dependence of the oscillation amplitude, and its dependence on magnetic field is used to determine the quantum scattering time and the value of the carrier concentration fluctuations.
32(2006); http://dx.doi.org/10.1063/1.2161934View Description Hide Description
A study is made of the energy spectrum of electrons localized in cylindrical nanochannels coated by a thick layer of solid hydrogen or neon. The interaction potential of an electron with the surrounding matter is determined. An algorithm, which includes both analytic and numerical calculations, is devised for solving the wave equation. The dependence of the electron energy on the radius of the channel is investigated, and the electron wave functions are determined. The influence of a helium film on the energy state of the electron is considered. It is shown that at channel radii of the order of 50Å the localization of the electron inside the channel is energetically favorable.
32(2006); http://dx.doi.org/10.1063/1.2161935View Description Hide Description
The profile of injected charges in a -based field-effect transistor (FET) is considered. A simple scheme for calculations of the charge distribution between the 2D layers of molecules is founded on a small magnitude of the interball electron hopping. Analytical solutions of the equations for the charge distributions are obtained in the limits of thick and thin crystals. The charge density is shown to drop exponentially with the crystal depth. The calculations predict the relative part of induced charges involved in the surface layer to be and in the cases of electron and hole injection, respectively.