Magnetophonon Resonance in a Two-Dimensional Electron System in the GaAs–AlxGa1-xAs Heterojunction Interface

Abstract

Magnetophonon resonance in a two-dimensional electron system at the interface of GaAs–Al _x Ga _{1- x} As heterojunction was investigated using pulsed high magnetic fields up to 35 T. The fundamental peaks with a harmonic number N =1 was observed for the first time. The polaron mass of 0.0745±0.0015 m _e was determined by the analysis of the oscillatory resistance change using the LO phonon energy of GaAs. This value was successfully interpreted in terms of the non-parabolicity of the conduction band in GaAs taking into account the two dimensionality of the electronic state. A remarkably large damping of the oscillation was observed in spite of the large electron mobility.