半Heusler型拓扑绝缘体LaPtBi能带调控的研究  

Investigation on regulating the topological electronic structure of the half-Heusler compound LaPtBi

作　　者：张小明[1,2] 刘国栋[1] 杜音[2] 刘恩克[2] 王文洪[2] 吴光恒[2] 柳忠元[3] 

机构地区：[1]河北工业大学材料学院,天津300130 [2]中国科学院物理研究所磁学国家重点实验室,北京100190 [3]燕山大学材料学院,秦皇岛066004

出　　处：《物理学报》2012年第12期173-181,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51171207);国家基金委创新研究群体(批准号:51020161)资助的课题~~

摘　　要：采用基于密度泛函理论的全势能线性缀加平面波的方法,研究了化学替代和施加等体积单轴(拉、压)应力两种方式对半Heusler型拓扑绝缘体LaPtBi能带的影响.计算结果表明,通过在LaPtBi合金中用Sc元素替换La,或者用Pd替换Pt,都可以使得原本受立方对称性保护的Γ_8能带在费米能级附近打开一带隙;而对于施加等体积单轴应力来扭曲立方晶格的方式,在使得Γ_8能带打开的同时,还可以实现对费米能级位置有规律地调控,使LaPtBi合金最终成为真正意义上的体材料是绝缘性而表面是金属性的拓扑绝缘体.Using the full-potential linearized augmented plane-wave method based on the density functional theory, we investigate the influences of chemical substitution and uniaxial strain on the topological electronic structure of the half-Heusler compound LaPtBi. It is shown that the/78 band which is protected by the cubic symmetry of the Clb structure can open and form a gap by substituting Sc element for La or Pd for Pt in LaPtBi compound. However, in the case of distorting cubic lattice by using a uniaxial strain, not only the gap mentioned above appears, but also the Fermi level can be tuned regularly. Thus the LaPtBi compound becomes a real topological insulator.

关 键 词：第一性原理计算 拓扑绝缘体 半Heusler合金 

分 类 号：O469[理学—凝聚态物理]