Hole mediated magnetism in Mn-doped GaN nanowires

The hole-mediated magnetism in Mn-doped GaN nanowires is investigated using the k (.) p method and the mean-field model. The Curie temperature (T-C) as a function of the hole density p can be explained based on the calculated band structure of the nanowires. For low Mn concentration, T-C vs. p shows many peaks stem from the peaks of the one-dimensional density of states. When the Mn concentration is increased, T-C is enhanced, and the peaks of T-C versus p are fully merged by the thermal distribution of the holes in the valence band. It is found that the Curie temperature in Mn-doped GaN wire can be higher than room temperature, in agreement with experiment [Song et al., J. Phys.: Condens. Matter 17, 5073 (2005)]. The ferromagnetism in Mn-doped GaN wire is slightly anisotropic due to the small spin-orbit coupling. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3555092]