Impact Ionization in GaAs within A Screened Exchange Density Functional Formalism

S. Picozzi, R. Asahi, C. B. Geller, A. J. Freeman

Research output: Contribution to journalArticle

Abstract

We present the results of a fully first-principles calculation of impact ionization rates in GaAs within the density functional theory formalism, using a screened-exchange approach and the highly accurate all-electron full-potential linearized augmented plane wave (FLAPW) 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.

Original languageEnglish
Pages (from-to)421-424
Number of pages4
JournalJournal of Computational Electronics
Volume1
Issue number3
DOIs
Publication statusPublished - Oct 1 2002

Fingerprint

Impact ionization
Gallium Arsenide
Ionization
Density Functional
Ion exchange
formalism
ionization
Energy
Electrons
Electron
Ab Initio Calculations
Pseudopotential
First-principles Calculation
Density functional theory
K-space
Conservation
Momentum
Energy gap
Anisotropy
Band Gap

Keywords

  • density functional theory
  • GaAs
  • impact ionization

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Modelling and Simulation
  • Electrical and Electronic Engineering

Cite this

Impact Ionization in GaAs within A Screened Exchange Density Functional Formalism. / Picozzi, S.; Asahi, R.; Geller, C. B.; Freeman, A. J.

In: Journal of Computational Electronics, Vol. 1, No. 3, 01.10.2002, p. 421-424.

Research output: Contribution to journalArticle

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