论文标题
对gan中的Mn $^{3+} $ ions的磁响应的晶体场模型模拟
Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn$^{3+}$ ions in GaN
论文作者
论文摘要
在一系列\ textIt {ab intio}和紧密的结合计算中预测了局部MN旋转之间的铁磁耦合，并对稀释的磁性半导体GA $ _ {1-x} $ Mn $ _x $ n进行了实验验证。在小型MN浓度的极限，$ x \ lyssim 0.01 $，使用单个离子晶体场模型方法成功地描述了该材料的顺磁性。为了在存在相互作用的磁中心的情况下（GA，MN）N中的磁化描述，我们通过考虑Mn $^{3+} $ ions的Mn $^{3+} $ ions的三胞胎和四重奏组的单个替代Mn $^{3+} $ ion的先前模型。使用这种方法，我们调查了磁性特性，尤其是单轴各向异性场的大小如何随着给定群集中的磁性Mn $^{3+} $离子的数量而变化，然后利用我们的模拟在解释GA $ _ {1-X $ $ $ _ $ _ $ x的实验磁性中的模拟。意义。结果，在GAN中Mn $^{3+} $ ions之间的交换耦合值的值大约上限和上限，在最近的邻居中$ j _ {\ Mathrm {nn}} $与下一个最近的邻居$ J _ {\ Mathrm {nnn}} $位置，分别是已有的。
A ferromagnetic coupling between localized Mn spins was predicted in a series of \textit{ab initio} and tight binding calculations and experimentally verified for the dilute magnetic semiconductor Ga$_{1-x}$Mn$_x$N. In the limit of small Mn concentrations, $x \lesssim 0.01$, the paramagnetic properties of this material were successfully described using a single ion crystal field model approach. In order to obtain the description of magnetization in (Ga,Mn)N in the presence of interacting magnetic centers, we extend the previous model of a single substitutional Mn$^{3+}$ ion in GaN by considering pairs, triplets and quartets of Mn$^{3+}$ ions coupled by a ferromagnetic superexchange interaction. Using this approach we investigate how the magnetic properties, particularly the magnitude of the uniaxial anisotropy field, change as the number of magnetic Mn$^{3+}$ ions in a given cluster increases from 1 to 4. Our simulations are then exploited in explaining experimental magnetic properties of Ga$_{1-x}$Mn$_x$N with $x \cong 0.03$, where the presence of small magnetic clusters gains in significance. As a result the approximate lower and upper limits for the values of exchange couplings between Mn$^{3+}$ ions in GaN, being in nearest neighbors $J_{\mathrm{nn}}$ and next nearest neighbors $J_{\mathrm{nnn}}$ positions, respectively, are established.
