Effects of Longitudinal Magnetic Field on Ultrasound in Highly Doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-Type InSb

Abstract

We have studied the effect of a longitudinal dc magnetic field on the propagation of ultrasound in highly doped $n$-type InSb by using a quantum treatment which is valid at high frequencies and in strong magnetic fields. The interaction of conduction electrons with the ultrasound is via deformation-potential and piezoelectric-coupling mechanisms. It is found that the absorption coefficient depends strongly on the sound frequency and longitudinal dc magnetic field. Some oscillations in the absorption coefficient occur in the region of high frequencies. There exist some discontinuities in these oscillations in the region of strong magnetic fields and high frequencies. However, the sound velocity for the ultrasound propagating parallel to the dc magnetic field depends only on the ultrasonic frequency and no oscillations occur in the change in sound velocity at high frequencies.