Ultrasonic Attenuation in n-Type Ge. II. Effects of Uniaxial Stress

The stress dependence of the ultrasonic attenuation α( X ) in Sb doped Ge was measured at low temperatures over the wide concentration region 3.3×10 15 to 1.6×10 18 cm -3 . In the intermediate concentration region the behavior of α( X ) at low stresses is different from that observed in the low concentration region except the sample with 3.1×10 16 Sb cm -3 . A simple model is proposed which explains qualitatively the experiment in the lower part of the intermediate region. In the high concentration region a free electron gas model can explain the behavior of α( X ) provided that the existence of a single relaxation time τ is assumed in this system. The values of τ estimated based on this model are consistent with those in the stress free case.