【摘要】 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—A1N(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.更多还原

【Abstract】 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.更多还原