Magnetophonon resonance under hydrostatic pressure in GaAs-Al0.28Ga0.72As and Ga0.47In0.53As-Al0.48In0.52As heterojunctions.

Abstract

We report magnetophonon resonance measurements under hydrostatic pressure in GaAs-${\mathrm{Al}}_{0.28}$${\mathrm{Ga}}_{0.72}$As and ${\mathrm{Ga}}_{0.47}$${\mathrm{In}}_{0.53}$As-${\mathrm{Al}}_{0.48}$${\mathrm{In}}_{0.52}$As heterojunctions. The effective mass and the amplitude of the oscillations are measured in the range 150--300 K under pressures up to 16 kbar. The observed enhancement of the effective mass above its band-edge value has a relative amplitude of the order of 10% and 30% in the GaAs- and ${\mathrm{Ga}}_{0.47}$${\mathrm{In}}_{0.53}$As-based heterojunctions, respectively. In its major part, the mass enhancement can be explained by band nonparabolicity. We discuss the possible influence of magnetic-field-dependent screening of the electron-phonon interaction which brings changes in the polaron correction of the effective mass and in the amplitude of the magnetophonon oscillations.