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运用原子团模型研究了稀磁半导体GaN掺Cr的局域电子结构和磁性,计算采用基于密度泛函理论的离散变分方法．计算结果表明Cr原子的磁矩随掺杂浓度有明显的变化,变化趋势和实验结果吻合．在包含两个Cr原子的体系中,Cr原子之间是铁磁性偶合,每个Cr原子的磁矩与相同浓度下掺杂一个Cr原子的磁矩相近．对于不同的掺杂浓度,Cr原子与最近邻N原子之间均为反铁磁偶合,Cr原子的3d电子与N原子的2p电子之间有很强的杂化,这与晶体的能带计算方法得到的结果一致．
The local electronic structure and magnetic properties of GaN doped with rare earth doping GaN have been studied by using atomic cluster model. The discrete variational method based on density functional theory is used in the calculation. The calculated results show that the magnetic moment of Cr atoms changes obviously with the doping concentration, and the change trend agrees well with the experimental results. In systems containing two Cr atoms, the Cr atoms are ferromagnetically coupled, and the magnetic moment of each Cr atom is similar to that of a Cr atom doped at the same concentration. For different doping concentrations, the Cr atom and the nearest neighbor N atoms are antiferromagnetic coupling between the 3d electrons of Cr atoms and the 2p electrons of N atoms have a strong hybrid, which is related to the crystal band energy calculation The results obtained by the method are consistent.