2005/05/31 by Antônio J. R. da Silva, Antonio J. R. da Silva, A. Fazzio +3
Materials Science · Physics and Astronomy · #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #ZnO doping and properties #cond-mat.mtrl-sci #cond-mat.other
paper · pdf · doi:10.1103/physrevb.72.125208
arxiv created 2005/07/18 · openalex publication_date 2005/09/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We perform a theoretical study, using ab initio total energy density-functional calculations, of the effects of disorder on the Mn\ensuremath-Mn exchange interactions for Ga_1\ensuremath-xMnxAs diluted magnetic semiconductors. For a 128 atoms supercell, we consider a variety of configurations with 2, 3, and 4 Mn atoms, which correspond to concentrations of 3.1%, 4.7%, and 6.3%, respectively. In this way, the disorder is intrinsically considered in the calculations. Using a Heisenberg Hamiltonian to map the magnetic excitations, and ab initio total energy calculations, we obtain the effective Jn^Mn\ensuremath-Mn, from first (n=1) all the way up to sixth (n=6) neighbors. Calculated results show a clear dependence in the magnitudes of the Jn^Mn\ensuremath-Mn with the Mn concentration x. Also, configurational disorder and/or clustering effects lead to large dispersions in the Mn\ensuremath-Mn exchange interactions, in the case of fixed Mn concentration. Moreover, theoretical results for the ground-state total energies for several configurations indicate the importance of a proper consideration of disorder in treating temperature and annealing effects.