Quasi-one-dimensional polaron gas in a GaAs quantum wire
In this work we present a study of the plasmon-longitudinal-optical (LO) phonon collective excitation as a function of the quasi-one-dimensional wave vector for several electronic densities and thickness of the wires. We observed that the intra- and intersubband excitation collective energies are very sensitive to electronic density variation. This effect is more pronounced for the lower branch of the collective excitation energy and for narrower wires. Our calculations are performed using the Singwi, Tosi, Land and Sjolander (STLS) theory, at zero temperature, assuming a three-subband model, where only the first subband is occupied by electrons.
Plasmon-phonon coupling in one-dimensional semiconductor quantum-wire structures.
Collective excitation modes of coupled one-dimensional electron\char21{}longitudinal-optical-phonon systems (as occurring, for example, in GaAs quantum wires) are calculated in the mean-field approximation. In sharp contrast to higher-dimensional systems, the plasmon-phonon coupling is found to be strong at all densities. We also calculate the inelastic scattering rate of energetic quantum-wire electrons in the random-phase approximation, finding sharp thresholds in the scattering rate corresponding to the emission of coupled plasmon-phonon modes.
Hydrogenic impurity states in a quantum well wire
A variational calculation of hydrogenic impurity binding energies in quantum well wires has been performed. The binding of the hydrogenic impurity has been calculated as a function of the transverse dimensions of the wire. It is found that the binding energy of the hydrogenic impurity increases as the ratio of the Bohr radius of the impurity in a bulk semiconductor to the transverse dimension of the wire increases. To test the sensitivity of the binding energies to the trial wave function we have used in our calculations, we use a wave function of the same type to calculate the binding energy of hydrogenic impurities confined in a quasi‐two‐dimensional quantum well as a function of well width and compare our results for the binding energies to the results obtained by Bastard [Phys. Rev. B 24, 4714 (1981)].