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. Zh. éksp. Teor. Fiz. 115, 1478–1483 (April 1999)     

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. Zh. éksp. Teor. Fiz. 113, 1411–1428 (April 1998)     

Electron-phonon interaction and cyclotron resonance in two-dimensional electron gas

Results for the influence of electron-phonon interaction on the cyclotron effective mass and the resonance linewidth in a two-dimensional electron gas are presented. The temperature and magnetic field dependence is studied and the existence of quantum oscillations is demonstrated. It is shown that the relevant phonon frequency in typical MOS inversion layers is very small so that magneto-transport properties are temperature dependent even at a few degrees Kelvin. Results are consistent with the observed temperature, magnetic field and frequency dependence in Si(100) inversion layers.     

Submillimetre cyclotron resonance of electrons in GaP

The first observation of cyclotron resonance in n-type GaP is reported. The electrons were thermally excited at a temperature of 100 K and the resonance was observed at submillimetre wavelengths (337 μm) using a pulsed magnetic field of 0–300 kG. From experiments with B∥〈100〉, 〈110〉 and 〈111〉 it was found that the transverse effective mass for electrons is $\text{m}{}^1{}_{\mathrm{\perp }}\text{= 0.25 ± 0.01 m}{}_0$ and that the anisotropy factor for the conduction band ellipsoids is K = 20⁺¹⁰_-6.     

Shift in cyclotron resonance of electrons on liquid helium surfaces

We calculate the increase in cyclotron resonance frequency for electrons trapped within dimples on a liquid helium surface, when a vertical electric field is applied in addition to the strong vertical magnetic field.     

Splitting of the cyclotron resonance in two-dimensional electron systems

A large splitting of the cyclotron resonance line, observed in two different two-dimensional electron systems, remains unexplained. The splitting resembles an anti-level crossing with an unidentified mode of the semiconductor system. Here, we review our data on this splitting, and highlight some results of recent experiments.     

Microwave cyclotron resonance of hot electrons in p-type GaSb

A microwave photocreated cyclotron resonance signal is observed in p-type GaSb in the temperature range 1–30 K. Circular polarization and other measurements identify the carriers as electrons in the (000) conduction band. The problem of a surface effect on the measured peak position, reported for the first time is avoided by bulk carrier creation. An exponential loss of signal intensity at 27 K is explained by the theory of background plasma effects. The measured ωτ of 1·5–4 yields an electron collision time of τ ～ 10^?11 sec. The scattering mechanism at liquid helium temperatures is identified as being partly due to neutral defect acceptor scattering of hot electrons, with an unidentified residual scattering process. The electron polaron effective mass is measured to be (m *(polaron)/m₀) = 0·0412 ± 0·0012 for hot electrons with an average energy of ～ 14 MeV and is isotropic within 1 per cent. When corrections for conduction-band non-parabolicity and hot polaron effects are applied, the band-edge free electron mass is calculated to be (m₀*(free)/m₀) = 0·0396 ± 0·0021 (±5·2 per cent).     

Memory function for cyclotron resonance of two-dimensional electron systems

Coulomb effects on cyclotron resonance in two-dimensional electron systems are investigated based on a self-consistent approach which improves the random-phase approximation. The memory function in the dynamic magnetoconductivity depends on the electron density not only through the filling factor v but also on its combination with the dimensionless density parameter r_s in the form $\text{r}{}_{\mathrm{s}}\text{v}{}^{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$. The memory function reproduces the data of Wilson, Allen and Tsui for intermediate densities.     

Contribution of spin-orbit interaction to the magnetic susceptibility of interacting electrons in metals

The effect of spin-orbit interaction on the magnetic susceptibility of metals has been investigated using a pseudopotential formalism. The orbital spin and spin-orbit contributions to the magnetic susceptibility of Zn and Cd have been calculated. An important feature is that the spin-orbit contribution is diamagnetic and is of the same order of magnitude as orbital contribution in the case of Zn and Cd.     

Optical conductivity of a two-dimensional electron liquid with spin-orbit interaction

The interplay of electron-electron interactions and spin-orbit coupling leads to a new contribution to the homogeneous optical conductivity of the electron liquid. The latter is known to be insensitive to many-body effects for a conventional electron system with parabolic dispersion. The parabolic spectrum has its origin in the Galilean invariance which is broken by spin-orbit coupling. This opens up a possibility for the optical conductivity to probe electron-electron interactions. We analyze the interplay of interactions and spin-orbit coupling and obtain optical conductivity beyond RPA.     

On the temperature dependent cyclotron resonance lineshape of inversion-layer electrons in Si

Unlike the electron-impurity interaction, the electron-acoustic phonon interaction generates a temperature-dependent cyclotron resonance lineshape. The difference is due to the temperature-dependent phonon distribution and the quasi-inelastic nature of the electron-phonon scattering. Calculations based on the proper connected diagram expansion are in qualitative agreement with experiments on inversion-layer electrons in Si in the temperature range 8–65 K.     

Rashba spin-orbit interaction and shot noise for spin-polarized and entangled electrons

We study shot noise for spin-polarized currents and entangled electron pairs in a four-probe (beam-splitter) geometry with a local Rashba spin-orbit (s-o) interaction in the incoming leads. Within the scattering formalism we find that shot noise exhibits Rashba-induced oscillations with continuous bunching and antibunching. We show that entangled states and triplet states can be identified via their Rashba phase in noise measurements. For two-channel leads, we find an additional spin rotation due to s-o induced interband coupling which enhances spin control. We show that the s-o interaction deter-mines the Fano factor, which provides a direct way to measure the Rashba coupling constant via noise.     

Cyclotron resonance of two-dimensional electrons forming wigner crystal

The cyclotron resonance peak shape is analysed for two-dimensional electrons interacting with surface vibrations of a medium. Explicit expressions for the broadening and shift of the peak are obtained at low and high electron densities.     

Theory of cyclotron resonance width for electrons inelastically scattered by phonons

The cyclotron resonance width for a semiconductor under extreme high fields is calculated with the assumptions that electrons are scattered by acoustic phonons inelastically. The numerical results are in very good agreement with the recent experiments on Ge by Miura et al. (T ～ 300 K, B ～ 97 tesla). The energy-dependent widths arising from the relaxation processes with absorption and emission of a phonon show quite distinctive behaviors at low electron energies. At extreme low temperatures when few phonons are present, the width arising from the zero-point motion of the lattice is finite but very small. The charged-impurity scattering with the density as low as 10¹² cm^?3 numerically dominate the width due to the electron-phonon interaction below 10 K. The present theory supplements the previous work by Suzuki et al. where the elastic-scattering and high-temperature approximation were used.     

Edge spin currents in two-dimensional electron gas with spin-orbit interaction

Edge spin currents existing in two-dimensional electron gas near the boundary between the regions with spin-orbit interaction and without it are st udied for nonequilibrium conditions due to an electron current flowing parallel or normal to the boundary. The parallel current generates an edge spin density, whereas the normal one changes the edge spin current by a value proportional to the particle current.     

电子回旋共振放电中电子与微波互作用特性的粒子模拟和蒙特卡罗碰撞模拟

对电子回旋共振（ECR）放电电离过程中的电子与微波互作用特性进行了理论分析与数值模拟.采用粒子模拟（PIC）方法描述带电粒子与微波的互作用,采用蒙特卡罗碰撞（MCC）方法描述粒子间碰撞过程及带电粒子与边界的相互作用.编写了准三维的PIC/MCC数值模拟程序,并对放电过程中电子能量与微波场随时间、空间的演化进行了数值诊断. 关键词： 电子回旋共振放电 粒子模拟 蒙特卡罗方法 电离     

A note on the negative absorption of electromagnetic waves at the cyclotron resonance of plasma electrons

The quantum interpretation of the negative absorption of electromagnetic waves at the cyclotron resonance of plasma is given, and the conditions under which the negative absorption takes placs are examined.     

Quantum theory of the cyclotron resonance lineshape for a two-dimensional electron-phonon system

Mössbauer spectra of ¹³³Cs implanted in diamond show the growth of an amorphous layer with increasing ion dose. The annealing of this layer after heat treatment has also been observed.