L. I. Magarill

Ballistic transport and spin-orbit interaction of two-dimensional electrons on a cylindrical surface

The components of the ballistic magnetoconductance tensor of a two-dimensional electron gas placed on a cylindrical sector are calculated for various geometries. For a quasiclassical system a method is proposed for finding the conductance based only on the Bohr-Sommerfeld quantization condition and not requiring a knowledge of the matrix elements of the velocity. The effect of curvature of the surface on the spin-orbit interaction in a two-dimensional electron gas is investigated. As examples, the microwave absorption and longitudinal conductance of a hollow cylindrical wire are calculated, and also the conductance of a cylindrical sector. There are qualitative differences from planar systems, in particular the relative sign of the curvature and the spin-orbit coupling constant becomes important.

Kinetics of two-dimensional electrons on a curved surface

A number of effects associated with the curvature of the surface on which a two-dimensional (2D) electron gas is placed are studied. The most significant effect in an external magnetic field (which for 2D electrons becomes effectively nonuniform) is the lifting of the degeneracy of the Landau levels. The intensity and shape of the cyclotron resonance line (inhomogeneously broadened) for different polarizations and the corrections to the Hall constant are found for the example of a circular cylinder. A picture of the quantization of the conductance that is qualitatively different from the case of a flat strip is obtained for a quasi-one-dimensional quantum wire in the form of a hollow cylinder. It is shown that in contradistinction to the planar case the spectrum of 2D electrons on the curved surface is sensitive to the sign of the spin-orbit coupling constant (for a fixed sign of the curvature). For hetero-junctions, for example, this opens up new possibilities for extracting information about their “hidden parameters.”

Spin orientation of electrons by lateral electric field in 2D system without inversion symmetry

Abstract Spin polarization in 2D system caused by a lateral electric field is studied taking into account both Rashba and Dresselhaus mechanisms of spin–orbit interaction.a

Scattering processes in a two-dimensional semimetal

The scattering mechanisms in a two-dimensional semimetal based on a HgTe quantum well, where the electron and hole densities are controlled over a wide range by applying the gate voltage, have been studied. It is shown that impurity scattering prevails in this system at low temperatures. Interparticle scattering (in this case, electrons and holes) has been observed to directly affect the resistance of the metal.

Effect of curvature of a 2D electron sheet on the ballistic conductance and spin–orbit interaction

Abstract Energy spectrum and ballistic transport of 2D electrons placed on the cylindrical surface are theoretically considered. The curvature results in two types of effects: (1) the spatial inhomogeneity of the normal component of the magnetic field smears the steps in the dependence of the conductance on Fermi energy and (2) spin–orbit interaction in a curved space changes qualitatively due to lifting up the degeneracy with respect to the sign of spin–orbit constants.

Spin-plasmon oscillations of the two-dimensional electron gas

Interaction of the spins of 2D electrons with an alternating electric field in the plane of the system is considered. It is assumed that the double spin degeneracy is eliminated by the spin-orbit splitting. It is shown that transitions between different spin states produce a narrow absorption band in the degenerate electron gas. In the frequency domain corresponding to these transitions, those frequencies are combined with two-dimensional plasmons; as a result, the plasmon spectrum is modified, and a new type of oscillations occurs, namely, a spin-plasmon polariton. The dispersion law of these oscillations is derived. The problem of the excitation of spin-plasmon polaritons by an external electromagnetic field is solved.

Influence of spin-orbit interaction of two-dimensional electrons on the magnetization of nanotubes

Calculations are made of the magnetization of a nanotube in a longitudinal magnetic field. It is shown that the spin-orbit interaction of two-dimensional electrons located at the surface of the nanotube causes a qualitative change in the magnetization. Depending on the parameters of the system, either diamagnetism or paramagnetism can occur and the dynamic susceptibility is characterized by anomalous dispersion at low frequencies.

Optical and photoelectric properties of helical quantum wires

The appearance of a steady current in a helical quantum wire under circularly polarized light is predicted. The effect is associated with the appearance of a travelling electromagnetic wave in the coordinate system related to the wire, the wavelength being determined by the period of the helix. The gyrotropy of a medium consisting of parallel quantum wires is considered.

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.

Spin Response of 2D Electrons to a Lateral Electric Field

The spin orientation of two-dimensional (2D) electrons by a lateral electric field is considered. The electron dispersion law is assumed to contain linear terms due to the spin-orbit band splitting in an asymmetric quantum well. The coefficient of spin orientation in a DC electric field is found. The mean electron spin is oriented in the sample plane perpendicularly to the electric field. The interaction of an AC electric field with spins of 2D electrons is studied. It is shown that transitions between different spin states give rise to a narrow absorption band. These states are mixed with 2D plasmons in the frequency range related to these transitions, with the result being that the plasmon spectrum is modified and a new type of oscillations arises (spin-plasmon polariton). The problem of the generation of spin-plasmon polaritons by an external field is solved.