Local lattice distortions around $\mathrm{M}{\mathrm{n}}^{2+}$ cause in-plane uniaxial magnetic anisotropy in Ga(Mn)As

Abstract

We theoretically investigate the interplay between local lattice distortions around $\mathrm{M}{\mathrm{n}}^{2+}$ ion impurity and the ion's magnetic polarization, mediated through spin-orbit coupling of hole. We show that the tetrahedral symmetry around $\mathrm{M}{\mathrm{n}}^{2+}$ ion impurity is spontaneously broken even in the paramagnetic regime. Modest local lattice distortions around the impurity $\mathrm{M}{\mathrm{n}}^{2+}$ ion, along with the growth strain, stabilize magnetization along $<110>$ directions, in the ferromagnetic regime. We explain the experimentally observed in-plane uniaxial magnetic anisotropy seen in this system using this symmetry-breaking mechanism.

arXiv comment12 pages, 9 figures, 2 tables