Temperature dependence of the electron mobility in GaAs-GaAlAs heterostructures

We have studied the temperature dependence of the mobility of two-dimensional electron gases formed at the interface of high-quality GaAs-GaAlAs heterostructures, focusing on the temperature range 4-40 K. The inverse mobility is shown to increase linearly with temperature, with a slope which increases with the electron density and is independent of the zero-temperature mobility. The results are consistent with a theoretical model for the acoustic-phonon mobility that includes screening, indicating that the temperature dependence in high mobility GaAs-GaAlAs structures is dominated by phonons rather than ionized impurities. A good agreement between theory and experiment is found using a value of 13.5 eV for the deformation potential of GaAs.