Heat Capacity and Elastic Constants of CsI at Low Temperatures

Abstract
Measurement of the heat capacity from 2.13° to 10°K and of the elastic constants at 4.2°K have been made on a single crystal of CsI. The Debye temperature at 0°K, θ0, as calculated from the heat capacity is θ0=127.67°K. Values of the elastic constants at 4.2°K are c11=2.725±0.6%, c44=0.873±0.6%, and c12=0.767±3% in units of 1011 dyn/cm2. θ0 calculated from the elastic constants at 4.2°K is equal to 129.4°K.