半哈斯勒化合物XYZ(X=Li,Na,K;Y=Ag,Au;Z=S,Se,Te)拓扑性质的第一性原理研究  

Topological Properties of Half Heusler Compounds XYZ (X=Li,Na,K;Y=Ag,Au;Z=S,Se,Te):Frist Principles Study

作　　者：袁秋林[1,2] 王广涛 YUAN Qiulin;WANG Guangtao(College of Physics,Henan Normal University,Xinziang 453007;College of Electronic and Electrical Engineering,Henan Normal University,Xinziang 453007)

机构地区：[1]河南师范大学物理学院,新乡453007 [2]河南师范大学电子与电气工程学院,新乡453007

出　　处：《低温物理学报》2023年第1期30-37,共8页Low Temperature Physical Letters

基　　金：河南省高校基金重点科研项目(编号:19zx008);河南师范大学高性能计算中心(HPC)资助的课题。

摘　　要：利用密度泛函理论和k·p模型方法对半哈斯勒化合物XYZ(X=Li,Na,K;Y=Ag,Au;Z=S,Se,Te)进行了研究.半哈斯勒化合物XYZ可以看作是由X^(n+)离子填充到闪锌矿YZ^(n-)晶格组成.它们的s态电子形成双重简并Γ_(6)^((2))能带,p-d杂化态形成双重简并Γ_(7)^((2))能带和四重简并Γ_(8)^((4))能带.当s型的Γ_(6)^((2))能带高于Γ_(7)^((2))和Γ_(8)^((4))能带时,化合物为普通绝缘体.然而,当s型Γ_(6)^((2))能带低于Γ_(7)^((2))和Γ_(8)^((4))能带时,化合物是拓扑非平庸绝缘体(如NaAuS)或半金属(如NaAuTe),这还要取决于负或正的自旋轨道耦合(SOC)效应.本文以NaAuS/NaAuTe两种材料为例,揭示了这种有效的SOC可以通过S-3p/Te-5p和Au-5d态之间的p-d杂化来调节,从而为我们设计拓扑材料提供了思路和方法.The topological properties of Half Heusler compounds XYZ with X=Li,Na,K;Y=Ag,Au;Z=S,Se,Te were investigated by density functional theory and k·p model Hamiltonian.The XYZ half Heusler compounds can be regarded as consisting of the X~(n+)ions stuffing into the ZincBlende YZ~(n-)sub-lattice.Their s-state electrons form double degeneratedΓ_6~((2))bands,while their p-d hybridized states form double degeneratedΓ_7~((2))and fourfold degeneratedΓ_8~((4))bands.When the s-likedΓ_6~((2))bands lie above theΓ_7~((2))andΓ_8~((4))bands,the compounds are normal insulator.However,when the s-likedΓ_6~((2))bands lie below theΓ_7~((2))andΓ_8~((4))bands,the compounds are topological nontrivial insulator(NaAuS)or semimetal(NaAuTe),depending on the negative or positive effective Spin-Orbit-Coupling(SOC).We take NaAuS and NaAuTe as examples,such effective SOC can be tuned by the p-d hybridization between S-3p/Te-5p and Au-5dstates.Therefore,we can design topological materials by these methods.

关 键 词：半哈斯勒化合物 拓扑性质 自旋轨道耦合 轨道杂化 

分 类 号：O469[理学—凝聚态物理]