Collapse of High Field Magnetophonon Resonance in GaAs-GaAlAs Heterojunctions

Abstract

Magnetophonon resonance is studied in the resistivity of high mobility GaAs-GaAlAs heterojunctions. In contrast to previous studies which show an exponentially damped series of oscillations, we find this only at low magnetic fields. At high fields the oscillation amplitude decreases, leading to collapse of the fundamental resonance. Fully self-consistent calculations, including all scattering processes, show that Landau level width oscillates in field and explain this unusual behavior.