Theory of self-diffusion in GaAs

TL;DR

This paper uses ab initio molecular dynamics to study the gallium vacancy migration mechanism and self-diffusion in GaAs, revealing a second nearest neighbor hop mechanism and aligning well with experimental data.

Contribution

It provides new insights into the migration mechanism and self-diffusion rate of gallium vacancies in GaAs through ab initio simulations.

Findings

Gallium vacancy migrates via second nearest neighbor hops

Calculated self-diffusion constant agrees with isotope heterostructure experiments

Results differ from earlier interdiffusion experiment estimates

Abstract

Ab initio molecular dynamics simulations are employed to investigate the dominant migration mechanism of the gallium vacancy in gaas as well as to assess its free energy of formation and the rate constant of gallium self-diffusion. our analysis suggests that the vacancy migrates by second nearest neighbour hops. the calculated self-diffusion constant is in good agreement with the experimental value obtained in ^69 GaAs/ ^71 GaAs isotope heterostructures and at significant variance with that obtained earlier from interdiffusion experiments in GaAlAs/GaAs-heterostructures.