Ab initio characterization of arsenic vacancy diffusion pathways in GaAs with SIEST-A-RT

We use the SIEST-A-RT simulation technique to study in detail arsenic vacancy self-diffusion mechanisms in GaAs. Vacancy self diffusion is of fundamental importance for the understanding of semiconductor nanostructure formation. We find that the dominant mechanism for both -1 and +1 charge states is the plane-passing jump to the second neighbour. Contrary to the Ga vacancy, the height of the activation barrier is essentially independent of the charge state. Other, less probable, diffusion mechanisms are also discussed.