ELECTRON-ELECTRON INTERACTIONS IN THE NONPARABOLIC CONDUCTION-BAND OFNARROW-GAP SEMICONDUCTORS

The Lindhard dielectric function is evaluated at nonzero temperatures with Fermi-Dirac statistics and a nonparabolic conduction band for bul k, narrow-gap semiconductors. This is used to study two problems of cu rrent interest: (i) inelastic scattering of single, energetic electron s by a system of plasmons, phonons, and quasiparticle excitations; and (ii) cooling of a hot, quasiequilibrium plasma by dynamically screene d LO-phonon emission. Scattering of high-energy electrons injected int o n-doped InAs at room temperature is analyzed and compared to the cas e where nonparabolicity is neglected. Plasmon losses and a larger dens ity of states are shown to be more important for electrons in a nonpar abolic conduction band with energy above the Fermi level. The energy-l oss rate of a hot-electron-donor ion plasma to a cold lattice via scre ened LO-phonon emission in parabolic and nonparabolic bands is also ob tained. It is found that even though dynamic screening of LO phonons i s stronger in a nonparabolic band, the cooling rate of hot electrons i n InAs can be significantly faster because of the increased density of conduction-band states. [S0163-1829(98)04916-9].