Diffusion and clustering of substitutional Mn in (Ga,Mn)As

Hannes Raebiger, Maria Ganchenkova, Juhani von Boehm
2006 Applied Physics Letters  
The Ga vacancy mediated microstructure evolution of (Ga,Mn)As during growth and post-growth annealing is studied using a multi-scale approach. The migration barriers for the Ga vacancies and substitutional Mn together with their interactions are calculated from first principles, and temporal evolution at temperatures ranging from 200 to 350^∘C is studied using Lattice Kinetic Monte Carlo simulations. We show that at the typical growth and annealing temperatures (i) gallium vacancies provide the
more » ... diffusion mechanism for substitutional Mn and (ii) in 10--20 h the vacancy mediated diffusion of Mn promotes the formation of substitutional clusters. Clustering reduces the Curie temperature (T_C), and therefore the Mn clustering combined with the fast interstitial Mn diffusion explains the experimentally observed twofold annealing behavior of T_C.
doi:10.1063/1.2219337 fatcat:swn3hm33yjepfmt2in2qq2d2ii