The magnetophonon effect in III-V semiconducting compounds

Abstract

A systematic survey has been made with epitaxial films of n-type GaAs of the dependence of the position and amplitude of magnetophonon resistance oscillations on the experimental parameters of magnetic field, temperature and sample mobility. A number of corroborative experiments have also been performed with n-type InSb and InAs. With the magnetic field applied perpendicular to the current direction, a dependence of magnetophonon peak position on both temperature and mobility was found. A change in the curvature of the band edge can be deduced from the temperature dependence, and the low-frequency effective mass at the bottom of the conduction band of GaAs is found to be 0·0653m at 280 °K and 0·0675m at 70 °K. With InSb the band-edge mass of the electrons is found to be 0·0127m at 160 °K and 0·0134m at 60 °K. The dependence of the peak position on mobility is thought to be related to an expression describing the magnetic field dependence of the amplitude of the oscillatory terms. The amplitudes of the oscillatory terms do not depend on the mobility in a simple manner and appear to be a function of the number of ionized impurity sites rather than of the actual mobility of the sample.