University at Buffalo, State University of New York, Buffalo, NY 14226, USA.
J Phys Condens Matter. 2013 May 22;25(20):206005. doi: 10.1088/0953-8984/25/20/206005. Epub 2013 Apr 25.
We theoretically investigate the interplay between local lattice distortions around the Mn(2+) impurity ion and its magnetization, mediated through spin-orbit coupling of holes. We show that the tetrahedral symmetry around the Mn(2+) ion is spontaneously broken and that local Jahn-Teller distortions coupled with growth strain result in uniaxial magnetic anisotropy. We also account for the experimentally observed in-plane uniaxial magnetic anisotropy rotation due to variation of hole density. According to this model, lack of inversion and top-down symmetries of (Ga, Mn)As layers lead to in-plane biaxial symmetry breaking in the presence of Jahn-Teller distortions.
我们从理论上研究了通过空穴的自旋轨道耦合介导的 Mn(2+)杂质离子及其磁化之间的局域晶格畸变相互作用。我们表明,Mn(2+)离子周围的四面体对称性被自发打破,局部 Jahn-Teller 畸变与生长应变导致单轴各向异性磁各向异性。我们还考虑了由于空穴密度变化而导致的实验观察到的面内单轴各向异性磁各向异性旋转。根据该模型,在 Jahn-Teller 畸变存在的情况下,(Ga,Mn)As 层缺乏反转和自上而下的对称性导致面内双轴对称破坏。