Microscopic theory of intervalley scattering in GaAs: k dependence of deformation potentials and scattering rates

The ‘‘rigid-pseudoion’’ model is applied to intervalley scattering processes in GaAs. The intervalley deformation potentials (IDPs) that we obtain at high-symmetry points are in good agreement with previous calculations. We find that the IDPs show a strong dependence on the wave vector of the intervalley phonon, therefore a numerical integration over the Brillouin zone (e.g., with the tetrahedron method) is necessary to obtain realistic scattering rates that can be compared with those obtained from experiments. We calculate the lifetimes of electrons at the L and X valleys as a function of temperature (L: 2.2±0.5 ps; X: 130±20 fs at room temperature) and discuss our results in comparison with recent ultrafast laser experiments and Monte Carlo simulations. Finally, the IDPs show an anisotropy that might be important when simulating electrical transport in hot-electron devices.