Impact ionization in GaAs: a screened exchange density functional approach
Abstract
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 (FLAPW) method. The calculated impact ionization rates show a marked orientation dependence in {\bf 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.
Keywords
Cite
@article{arxiv.cond-mat/0108400,
title = {Impact ionization in GaAs: a screened exchange density functional approach},
author = {S. Picozzi and R. Asahi and C. B. Geller and A. Continenza and A. J. Freeman},
journal= {arXiv preprint arXiv:cond-mat/0108400},
year = {2009}
}
Comments
11 pages, 4 figures, Submitted to Phys. Rev. B