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arXiv 1509.04419cond-mat.mes-hall
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Kane-Mele模型拓扑绝缘体中对称性保护的反常能带反转

An anomalous band inversion protected by symmetry in a topological insulator of the Kane-Mele model

Jie-Xiang Yu, J. G. Che

摘要:

通过在石墨烯衍生物上沉积Au,在$3\times 3$单元石墨烯中用3个N原子取代4个C原子,实现了一个Kane-Mele模型的拓扑绝缘体,在石墨烯的Dirac点周围具有50~meV的带隙.在这种材料中,我们观察到一个反常的带反转(BI)的保护下的对称性与字符$e$的C $_{\rm 3V}$。对称性约束了两个$e$带,其具有Au和N轨道的镜像对称组合(MSC)和镜像反对称组合(MAC),在$Γ$处简并,而石墨烯的$π^*$在$e$ -MAC带上的相互作用倾向于提升该简并,导致$π^*$和$e$ -MAC带在$Γ$附近交换它们的轨道分量,从而导致中断的BI。

英文摘要:

Depositing Au on a graphene derivate, which involves substituting four C atoms with three N atoms in a $3\times 3$ cell graphene, we realized a topological insulator of the Kane-Mele model with a gap of 50~meV surrounding the Dirac point of graphene. In this material, we observed an anomalous band inversion (BI) protected by the symmetry with character $e$ of group C$_{\rm 3V}$. The symmetry constrains two $e$ bands with mirror-symmetry combination (MSC) and mirror-antisymmetry combination (MAC) of Au and N orbitals degenerate at $Γ$, whereas the interaction of $π^*$ of graphene on the $e$-MAC band tends to lift this degenerate, resulting in that the $π^*$ and $e$-MAC band exchange their orbital components near $Γ$, causing thus a discontinued BI.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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