Low Temperature Overheating Effect in SiGe p-Type Quantum Wells. Methods of the Hole-Phonon Energy Relaxation Time Determination

The temperature dependence of the hole-phonon energy relaxation time $τ_{hph}$ (T) under hot-hole conditions was studied in SiGe p-type quantum wells. The hot-hole temperature $T_{h}$ was estimated through three different experimental methods: (i) from a comparison of the amplitude of the Shubnikov-de Haas oscillations changed by current and temperature; (ii) from a comparison of the phase relaxation time in the effect of weak localization obtained either at different temperatures and minimum current or at different current at a fixed temperature; (iii) from a comparison of the temperature and current dependences of the sample resistance. The values of $T_{h}$ obtained by all three different methods were used to calculate, from the heat balance equation, the temperature dependence of the hole-phonon energy relaxation time $τ_{hph}$ (T). All three temperature dependences $τ_{hph}$ (T) were almost identical and demonstrated transition of the 2D system from "partial inelasticity" to small angle scattering at lower temperatures.