Scattering mechanisms in indium antimonide at low temperatures

Abstract

Investigations have been carried out into the scattering mechanisms responsible for the loss of energy and momentum in high-purity n-type InSb, in the temperature range below 77°K. The dominant momentum loss is due to ionized impurity scattering, as considered by Brooks and Herring, with modifications introduced by electron-electron interactions below 15°K, and scattering by the longitudinal optical and acoustic deformation potential modes at higher temperatures. Information on the electron-phonon interaction at lower temperatures is obtained from hot-electron measurements. The dominant mechanisms below 20°K are again thought to be due to the optical and acoustical deformation potential modes, but the situation is complicated by electron-electron effects. Little evidence is found of any effect due to scattering by the piezoelectric potential associated with the acoustical mode, certainly above about 8°K. These hot-electron measurements permit an estimate of the energy relaxation time of the electron system, and its dependence on temperature. Values are found which are in good agreement with those obtained more directly by pulse techniques. Throughout the work a value for the deformation potential constant of 30 ev has been assumed.