Cr掺杂浓度对AlN半金属性影响的第一性原理研究

本文基于密度泛函理论的第一性原理方法, 在广义梯度近似(GGA)下计算了掺杂过渡金属Cr原子后AlN晶体自旋极化的能带结构、分态密度等性质. 结果表明, 半金属能隙随着掺杂浓度的增大而减小. 文中以掺杂浓度为12.5%的Cr-AlN(2×2×1)为例, 分析了其自旋极化的能带结构、分态密度和磁矩等性质, 发现Cr-3d电子对自旋向下子带导带底的能量位置起决定作用. 随着掺杂浓度的增大, Cr原子间相互作用增强, Cr-3d能带向两边展宽, 导致自旋向下子带导带底的能量位置下降, 从而半金属能隙变窄.

Concentration's effect on the half-metallic properties of Cr doped AlN:first principles study

The half-metallic properties of transition metal Cr doped wurtzite AlN crystal were studied by density-functional theory using the generalized gradient approximation (GGA) for the exchange-correlation potential. The result indicates that the half-metallic gap decreases with increasing Cr doped concentrations. Analysis of the spin-polarized band structures, partial density of states (PDOS) and the molecular moment of Cr-AlN (2×2×1) shows that the conduction band minimum of down-spin bands is determined by Cr-3d states. The interaction between Cr atoms enhances and Cr-3d bands broaden with increasing Cr doped concentrations, which results in the decrease of the conduction band minimum of down-spin bands, so the half-metallic gap reduces.