Effect of Nonparabolic Band Structure on Longitudinal Magnetoacoustic Phenomena

Abstract

The effect of nonparabolic band structure on the propagation of ultrasound in a semiconductor such as $n$-type InSb in the presence of longitudinal magnetic fields is discussed using a quantum treatment which is valid at high frequencies and in strong magnetic fields. The absorption coefficient and sound velocity for ultrasound propagating parallel to the magnetic field are found to change with magnetic field. This dependence on magnetic field arises solely from the nonparabolicity of the energy bands and would be in addition to any magnetic field dependence due to a field-dependent relaxation time. A numerical calculation is performed for the case of $n$-type InSb and a comparison is made with the experimental results of Nill and McWhorter.