LiMgPbSb型四元Heusler合金CoFeTiSb的半金属性及其无序效应

The half-metallicity and disorder effect of quaternary LiMgPbSb-type Heusler alloys CoFeTiSb

基于密度泛函理论的GGA计算,我们研究了LiMgPbSb型Heusler合金CoFeTiSb电子结构,发现CoFeTiSb在费米面处存在100%的自旋极化率,并且具有2μB的原胞总磁矩.此外,我们考虑了Co-Fe、Co-Ti和Fe-Ti交换无序对CoFeTiSb合金电子结构的影响,发现这三种交换无序均使得CoFeTiSb完全丧失了半金属性,在Co-Fe交换无序下,CoFeTiSb合金具有85%的自旋极化率,而在Co-Ti无序下,CoFeTiSb合金的自旋极化率只有5%.

By using generalized gradient approximation （GGA） scheme within the density functional theory （DFT） , the electronic structures of quaternary LiMgPbSb - type Heusler alloy CoFeTiSb were investigated. The spin - polarization of 100% at the Fermi level and cell magnetic moment of 2 μB were detected. Furthermore, the influences of Co - Fe,Co - Ti and Fe - Ti swap disorder on its electronic structure have been concerned in CoFeTiSb alloy. As a result, the half- metallicity of CoFeTiSb alloy is destroyed by three swap disorder effects mentioned above. Only spin -polarization values of 85% for Co -Fe disorder and 5% for Co -Ti disorder are retained in CoFeTiSb alloy.