MANY-BODY TREATMENT OF HOT-ELECTRON SCATTERING FROM QUASI-EQUILIBRIUM ELECTRON-HOLE PLASMAS AND COUPLED PLASMON LONGITUDINAL-OPTIC-PHONON MODES IN GAAS

The interaction of hot electrons (200-300 meV) with neutral electron-hole plasmas in bulk GaAs is theoretically investigated over a range of plasma temperatures and densities. Results obtained using a self-consistent, three-band (electron, heavy-, and light-hole) random-phase approximation for the system's dielectric function, including the lattice susceptibility, are compared with simpler approximations for treating the screened interaction between the hot electrons and the coupled plasma-longitudinal-optic-phonon system. Emphasis is placed on estimating the relative importance of hot-electron plasma versus hot-electron-LO-phonon scattering rates, to the extent that these can be distinguished. The relevance of single-parameter descriptions of the hot-electron ''scattering-rate,'' such as the total scattering rate out of a well-defined momentum state versus the average energy-loss rate of the hot electron, is discussed; there, specific reference is made to a more complete simulation of experimentally determined hot-electron-plasma scattering rates based only on the differential scattering rate. The importance of including the inter-heavy-light-hole polarizability in the system's dielectric-response function is explicitly demonstrated, and scaling parameters are derived that allow simple estimates of the ratio of the hot electron's energy that is coupled to the system via the electron, versus the hole components of the plasma.