An atomistic model for the simulation of acoustic phonons, strain distribution, and Gruneisen coefficients in zinc-blende semiconductors

Olga L. Lazarenkova, Jet Propulsion Laboratory, California Institute of Technology
Paul von Allmen, Jet Propulsion Laboratory, California Institute of Technology
Fabiano Oyafuso, Jet Propulsion Laboratory, California Institute of Technology
Seungwon Lee, Jet Propulsion Laboratory, California Institute of Technology
Gerhard Klimeck, Jet Propulsion Laboratory, California Institute of Technology; Network for Computational Nanotechnology, Electrical and Computer Engineering, Purdue University

Abstract

An accurate modeling of phonons, strain distributions, and Gr¨uneisen coefficients is essential for the qualitative and quantitative design of modern nanoelectronic and nanooptoelectronic devices. The challenge is the development of a model that fits within an atomistic representation of the overall crystal yet remains computationally tractable. A simple model for introducing the anharmonicity of the interatomic potential into the Keating two-parameter valence-force-field model is developed. The new method is used for the calculation of acoustic phonon and strain effects in zinc-blende semiconductors. The model is fitted to the Gr¨uneisen coefficients for long-wavelength acoustic phonons and reproduces the response to strain throughout the Brillouin zone in reasonable agreement with experiment.