Interaction of low-density 2DEG with acoustic phonons

Abstract

The energy relaxation of two-dimensional electron gas (2DEG) with low density (2.2×10 10 cm −2 ) in selectively-doped In 0.53 Ga 0.47 As/InP heterostructures has been studied over a range of electron temperatures 0.1 < T e < 2 K. The Joule power of the dc current was employed for heating the electron gas, with the four terminal ac resistance of the sample used as electron thermometer. We found that the interaction with a screened small-angle piezoelectric potential of the acoustic phonons dominates in the temperature range 0.1 < T e < 0.4 K. At higher temperatures 0.5 < T e < 1.5 K, the change of energy balance equation is associated with a gradual transition from the small-angle interaction to a quasi-elastic one. The screening of the electron-phonon interaction and the deformation potential of acoustic phonons must be taken into consideration in this temperature range. The best fit to the data was obtained with piezoelectric constant h 14 = (0.95 ±0.05)×10 7 V cm −1 and deformation potential E D = (6 ±1) eV for both temperature ranges.

High-frequency transport inp-typeSi∕Si0.87Ge0.13heterostructures studied with surface acoustic w

“…According to Ref. 22, screening of the hole-phonon interaction can be neglected if the screening wavevector q s exceeds the wavevector q ε of phonons with the average thermal energy, which in our case is q ε =8.2×10 5 cm −1 . Thus, q s ≫ q ε and the energy relaxation here is dominated unambiguously by unscreened acoustic phonon scattering so we should use γ=5.…”