B. Vinter

Self-consistent calculation of impurity scattering in inversion layers

Abstract The local density-functional method has been applied to the calculation of the influence of an ionized impurity on the electrons in an inversion layer on the surface of silicon. Compared to linear screening theories this theory shows improved agreement with experiments on the mobility. The bound state associated with the self-consistent potential has a very small binding energy.

Thomas-Fermi screening and level broadening in interacting two-dimensional electron-impurity systems

Abstract In this work we calculate the imaginary and the real parts of electronic self-energies as well as the one-electron spectral function for an interacting electron — impurity two-dimensional system as occurring in silicon inversion layers. We employ finite wave-vector Thomas-Fermi screening and Born approximation for the scattering. We calculate the electronic distribution function including, the impurity induced level broadening and find that the smearing of the Fermi surface due to impurity scattering is comparable with that due to the finite temperature effects. For quantitative comparison with experiments, both of these effects should be included.

Density-functional calculation of subband structure of Si inversion layers under stress

Abstract An extension of the local density-functional method has been used to study the population of the non-equivalent subbands in Si (100) inversion layers under uniaxial stress. The results are in fair agreement with the cyclotron resonance measurements, have important implications for gate-voltage swept SdH-oscillations, but do not resolve the conflict between the CR- and magnetic-field swept SdH-measurements.

Theory of impurity-induced infrared absorption in inversion layers

Abstract The frequency-dependent conductivity of electrons at a semiconductor-insulator interface which contains positively charged impurities has been calculated. The results in the low-density regime show marked differences between parallel and perpendicular polarization. In the highdensity limit the calculations predict a threshold on top of the Drude conductivity at a frequency just above the Fermi energy. The strength of the threshold indicates that it should be experimentally observable.

Subband energies in accumulation layers on InP

Abstract Resonant inelastic light scattering with incident photon energies close to the E0 + Δ0 optical gap in InP is used to study spin-flip single-particle and collective intersubband excitations in surface accumulation layers. The determined subband splittings and the depolarization shifts are compared with self-consistent calculations. From the obtained results it is concluded that the non-parabolicity of the conduction band cannot be neglected in the evaluation of the subband energies especially at high carrier concentrations.

Quantization of photo-excited carriers in GaAs doping superlattices

Abstract Photo-excited carriers in periodic doping multilayer structures of GaAs are studied using resonant inelastic light scattering techniques. Spin-flip single-particle intersubband excitations clearly demonstrate the quantization of electrons in purely space-charge induced potential wells. With increasing excitation intensity the electric subbands broaden to minibands with considerable dispersion with k perpendicular to the layers. A quasi-three-dimensional behavior is found in both self-consistent calculations and electronic Raman scattering experiments.