Magnetophonons in short-period superlattices

Abstract

We report the observation of magnetophonon resonances on the background of the longitudinal magnetoconductance in short-period GaAs/AlAs semiconductor superlattices. Both the GaAs and the AlAs longitudinal optical phonons are observed. We show how the enhancement of the magnetophonon effect with electric field is connected to the shift of the electron distribution towards the high-velocity and low-density-of-states region at the midpoint of the reduced Brillouin zone. The observed temperature dependence can be explained by considering the competition between the phonon population and the electron lifetime. The two superposed series of the GaAs and the AlAs optical phonons are shifted when hydrostatic pressure is applied and the relative strength of each series changes as the ⌫ miniband comes closer to the X states.

Superlattice magnetophonon resonances in strongly coupledInAs∕GaSbsuperlattices

“…Noguchi et al [22] also observed that low ∆ samples exhibited plateaus in the oscillatory part of the magnetoresistance trace which it was suggested may provide evidence for Polyanovskii's predictions. Detailed studies by Gassot et al [23] also assigned LMPR peaks as maxima in resistance but reported significant deviations from the predicted MPR conditions. The analysis of the GaAs/AlAs system is further complicated by the presence of resonances attributed to both the GaAs and AlAs LO phonons, which are approximately 25% different in energy.…”

Parallel magnetotransport in multiple quantum well structures

“…(9)). There are two papers know in which MPR was reported examined in superlattices and structures with MQW in the vertical transport (both the magnetic field and the electric current are perpendicular to layers) [20,21]. The present paper reports results of exploring MPR and MQW in the parallel transport.…”

“…In the case of MPR in a single heterostructure each transition between Landau levels corresponds with one peak (structureless) and the resonance fields were somewhat smaller from the theoretical position of MPRs involving the bulk LO phonon of GaAs. The authors [21], where an examination of MPR in the vertical transport in MQW GaAs-AlAs was reported, besides oscillations connected with the absorption of the quantum wells GaAs LO phonons also observed the peaks caused by interaction of electrons with LO phonons of the AlAs barrier. The partly observed peak structure can be explained by the introduction to MPR of two more kinds of barrier phonons.…”

Role of the Thermal Stress on the Magnetophonon Peak Structure in the Parallel Transport of the GaAs/AlGaAs Multiple Quantum Wells

“…There are two papers known in which MPR was examined in superlattices and structures with multiple quantum wells (MQW) in the vertical transport (both the magnetic field and the electric current are perpendicular to layers) [3,4]. The present paper reports results of the MPR research in MQW in the parallel transport (the magnetic field is perpendicular, and the current is parallel to layers).…”

“…Fd, 73.20.Dx The magnetophonon resonance (MPR) together with the cyclotron resonance has become one of the most widely applied methods of spectroscopy of electron states in semiconducting bulk crystals [1] and singular heterostructures [2]. There are two papers known in which MPR was examined in superlattices and structures with multiple quantum wells (MQW) in the vertical transport (both the magnetic field and the electric current are perpendicular to layers) [3,4]. The present paper reports results of the MPR research in MQW in the parallel transport (the magnetic field is perpendicular, and the current is parallel to layers).…”