第一性原理研究闪锌矿结构CrSe和CrAs半金属铁磁性的稳定性

First-principles study on stability of half-metallic ferromagnetism of zinc-blende CrSe and CrAs

运用第一性原理的全势能线性缀加平面波方法对闪锌矿结构CrSe和CrAs的电子结构进行自旋极化计算.闪锌矿结构CrSe和CrAs处于晶格平衡时都具有半金属性,它们自旋向下的电子能带带隙分别为3.38 eV和1.79 eV,同时,它们的自旋总磁矩分别为4.00和3.00μ_B/formula.自旋总磁矩主要来源于Cr的原子磁矩,Se和As的原子磁矩对总磁矩的贡献很小而且为负值,因而它们具有明显的铁磁性特征.使晶体晶格在±10%的范围内发生各向同性形变,对闪锌矿结构CrSe和CrAs的电子结构进行计算.计算结果表明,当晶格各向同性形变分别为-4%～10%和-2%～10%时,闪锌矿结构CrSe和CrAs仍然保持半金属铁磁性,并且总磁矩都稳定于4.00和3.00μ_B/formula.

Using the first-principles full-potential linearized augmented plane wave method, the spin-polarized calculations of electronic structure for zinc-blende CrSe and CrAs have been performed. Zincblende CrSe and CrAs at their equilibrium lattice constants are half-metallic with spin-down energy gaps of 3.38 and 1.97 eV and integer total magnetic moments of 4.00 and 3.00 μB/formula, respectively. The total magnetic moment comes mostly from magnetic moment on Cr, and Se and/or As contribute small but negative moment to it. The electronic structures of zinc-blende CrSe and CrAs have been calculated with the lattice uniform strain between --10 % and ＋ 10 %. The calculated results indicate that zinc-blende CrSe and CrAs can maintain half-metallic ferromagnetism and keep the total magnetic moments of 4.00 and 3.00 μB/formula from -4M to 10% and from --20% to 10% uniform strain, respectively.