Based on first-principles calculations, we predict that the monolayer AuTe2Cl is a quantum spin Hall (QSH) insulator with a topological band gap about 10 meV. The three-dimensional (3D) AuTe2Cl is a topological semimetal that can be viewed as the monolayer stacking along [Formula: see text] axis. By studying the energy-level distribution of [Formula: see text] orbitals of Te atoms for the bulk and the monolayer, we find that the confinement effect driven [Formula: see text] band inversion is responsible for the topological nontrivial nature of monolayer. Since 3D bulk AuTe2Cl has already been experimentally synthesized, we expect that monolayer AuTe2Cl can be exfoliated from a bulk sample and the predicted QSH effect can be observed.

中文翻译：

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单层 AuTe2Cl 中的限制效应驱动的量子自旋霍尔效应

基于第一性原理计算，我们预测单层 AuTe2Cl 是一种量子自旋霍尔 (QSH) 绝缘体，拓扑带隙约为 10 meV。三维 (3D) AuTe2Cl 是一种拓扑半金属，可以看作是沿 [公式：见文本] 轴堆叠的单层。通过研究体和单层的Te原子[公式：见文本]轨道的能级分布，我们发现限制效应驱动的[公式：见文本]能带反转是造成单层拓扑非平凡性质的原因。由于 3D 散装 AuTe2Cl 已经被实验合成，我们预计单层 AuTe2可以从大量样品中剥离 Cl，并且可以观察到预测的 QSH 效应。