Structural and magnetic properties of mn-based diluted magnetic semiconductors and alloys

Abstract

Direct supercell approach calculations of the magnetic exchange interactions in Mn-doped ScN was carried out in the local spin density approximation by using the muffin-tin-orbital Green's function method. We found that magnetic interactions are long range interactions and affected by the randomness, band gap corrections, and carrier concentrations. Using total energy minimization approach we found that the global energy minimum of MnN is obtained for zinc-blende structure. If the compound is compressed by 6, the energy minimum corresponds to the rock-salt structure in disagreement with the experimentally observed tetragonal distorted rock-salt structure, known asθ-phase. An isostructural phase transition for MnxSc 1-x N alloys from MnN θ-phase to h -ScN phase was found to occur at a hydrostatic pressure of 18GPa. We predict above room temperature Tc for Mn concentrations of about 10 in ScN:Mn system. © 2009 A. Alsaad.