Influence of defects on the lattice constant of GaMnAs

We study the influence of the major compensating defects As antisites and Mn interstitials known to occur in the GaMnAs ferromagnetic semiconductor on its structural properties. Our experimental results show that there is a balance between Mn interstitial and As antisite defects, leading to the reduced density of one type of defect upon increasing the density of the other defect. Significant differences in the lattice parameters of GaMnAs with different balances between these two types of defects were observed. The annealing-induced reduction of the GaMnAs lattice constant is inhibited in samples with a large density of As antisites.