The interaction of thermal phonons with conduction electrons in InSb. Application to heat-pulse spectroscopy

Abstract
High frequency ballistic phonons were radiated by the heat pulse method (To < 4.2 K) into degenerate n-type indium antimonide crystals. We first review the relevant aspects of the electron-phonon interaction : cut-off for phonon wavevectors larger than twice the Fermi radius (q > 2 kF), selective coupling of the longitudinal modes and screening effects. Then, we report original extensive measurements of phonon absorption as a function of the electron concentration in the semiconductor. The Fermi sphere acts as a high-pass filter, which enables phonon spectroscopy with no adjustable parameters. As a result, the frequency distribution of a heat pulse could be determined in a detailed fashion