Impact ionization in GaAs: A screened exchange density-functional approach
Results are presented of a fully ab initio calculation of impact ionization rates in GaAs within the density functional theory framework, using a screened-exchange formalism and the highly precise all-electron full-potential linearized augmented plane wave method. The calculated impact ionization rates show a marked orientation dependence in k space, indicating the strong restrictions imposed by the conservation of energy and momentum. This anisotropy diminishes as the impacting electron energy increases. A Keldysh type fit performed on the energy-dependent rate shows a rather soft edge and a threshold energy greater than the direct band gap. The consistency with available Monte Carlo and empirical pseudopotential calculations shows the reliability of our approach and paves the way to ab initio calculations of pair production rates in new and more complex materials.
- Research Organization:
- Bettis Atomic Power Laboratory (BAPL), West Mifflin, PA
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC11-98PN38206
- OSTI ID:
- 938976
- Report Number(s):
- B-T-3391; TRN: US0807196
- Country of Publication:
- United States
- Language:
- English
Similar Records
Impact ionization in semiconductors and hot-carrier injection in Si-MOSFETs
Band-structure dependence of impact ionization rate in GaAs