| 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Xn+离子填充到闪锌矿YZn?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。 |
| 关键词: 半哈斯勒化合物，拓扑性质，自旋轨道耦合，轨道杂化 |
| DOI： |
| 投稿时间：2023-01-11修订日期：2023-03-07 |
| 基金项目:河南省高校基金重点科研项目(编号19zx008) |
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| Topological properties of half Heusler compounds XYZ(X=Li, Na, K; Y= Ag, Au; Z=S, Se, Te):Frist Principles Studing |
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| Abstract: |
| The topological properties of Half Heusler compounds XYZ (with X=Li,Na,K; Y=Ag,Au; Z=S,Se,Te) are studied by density functional theory and K·P model Hamiltonian. The XYZ half Heusler compounds can be viewed as consisting of the Xn+ ions stuffing into the ZincBlende YZn? sub-lattice. Their s-state electrons form double degenerated Γ_6^((2)) bands, while their p-d hybridized states form double degeneratedΓ_7^((2))and fourfold degenerated Γ_8^((4)) bands. When the s-liked〖 Γ〗_6^((2)) bands are above the Γ_7^((2)) and Γ_8^((4)) bands, the compounds are normal insulator. However, when the s-liked Γ_6^((2))bands are below below the Γ_7^((2))and Γ_8^((4))bands the compounds are topological nontrivial insulator (NaAuS) or semimetal(NaAuTe), depended 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-5d states. So,we can design topological materials by these methods. |
| Key words: Half Heusler Topological properties Spin-Orbit-Coupling Orbital hybridization |