Guo-Qiang Hai

Intersubband‐coupling and screening effects on the electron transport in a quasi‐two‐dimensional δ‐doped semiconductor system

The effects due to intersubband coupling and screening on the ionized impurity scattering are studied for a quasi‐two‐dimensional electron system in δ‐doped semiconductors. We found that intersubband coupling plays an essential role in describing the screening properties and the effect of ionized impurity scattering on the mobility in a multisubband system. At the onset of the occupation of a higher subband, the screening due to the intersubband coupling leads to a reduction of the small angle scattering rate in the lower subband. We showed that such an effect is significant in a δ‐doped quantum well and results in a pronounced increase of the quantum mobility at the onset of the occupation of a higher subband.

Mobility of electrons in a quasi-one-dimensional conducting channel on the liquid helium surface in the presence of a magnetic field

The influence of the transverse magnetic field on the electron mobility in a quasi-one-dimensional channel along the liquid-helium surface is investigated. The mobility calculations are carried out by using the Boltzmann kinetic equation and the criteria for the validity of this approach, which are different from those for two-dimensional systems, are established. Two different limiting regimes corresponding to different roles of the electron-electron interaction in the quasi-one-dimensional electron system are considered. The mobility is shown to be a decreasing function of the magnetic field. It is shown that the temperature dependence of the mobility in the presence of the magnetic field, as in the case of zero field, is a nonmonotonic function.

Effects of intersubband interaction on multisubband electron transport in single and double quantum wells

The multisubband electron transport properties are studied for doped single quantum well and gated double asymmetric quantum well structures. The effects due to intersubband interaction and screening of the ionized impurity scattering are also investigated. We show that intersubband coupling plays an essential role in describing the screening properties as well as the effect of ionized impurity scattering on the mobility in a doped single quantum well. For coupled double quantum well structures, negative transconductance is found theoretically which is due to resonant tunneling between the two quantum wells.

Optical properties of δ-doped semiconductors: Plasmon–phonon coupling and Raman spectra

Abstract Collective excitations and their coupling to optical phonons have been studied for a two-dimensional electron gas in δ-doped polar semiconductors within the random-phase approximation. The inelastic light scattering spectrum due to the coupled plasmon–phonon modes are calculated for the multisubband two-dimensional electron systems. Our calculation shows that, due to the high electron density in these systems, both intrasubband and intersubband plasmons are strongly coupled to the optical-phonons. On the other hand, due to the high impurity concentration, level broadening modifies the inelastic light scattering spectrum significantly.

Mobility of electrons in a quasi-one-dimensional conducting channel on the liquid helium surface

The mobility of electrons scattered by ripplons and gas atoms in a quasi-one-dimensional channel on the surface of liquid helium is investigated theoretically. Nonmonotonic temperature dependence of the mobility below 0.5 K is predicted. Nonlinear effects leading to strong dependence of the mobility on driving electric field are also discussed. The calculations are carried out in the single-particle approximation and in the complete control regine which takes interelectron correlations into account. The results allow us to check the role of electron correlations in the system.

Energy states and kinetic properties of electrons in a quasi-one-dimensional channel over liquid helium in the presence of a transverse magnetic field

Single-particle energy states for electrons in a quasi-one-dimensional conducting channel on the surface of liquid helium in the presence of a magnetic field normal to the channel are calculated. The mobility of electrons along the channel is evaluated by the Boltzmann approach in the single-particle approximation and in the complete control approximation which takes interelectron correlations into account. The mobility is shown to be a decreasing function of magnetic field in a wide temperature range.