Propagation of Heat Pulses inp-Type Germanium under Uniaxial Stress

Absorption of phonons by stress-split acceptor states in germanium has been observed. A distinction is found between the "static" ($a^{*}q\ll 1$) and "dynamic" ($a^{*}q\gtrsim 1$) deformation potential constant ($a^{*}$ is the effective Bohr radius of impurity; $q$ is the wave number of relevant wave component), thus resolving an apparent conflict in previous reports. The effect of phonon scattering by isotopic impurities and of resonant phonon absorption results in phonon propagation in a well-defined frequency interval (phonon "window").