论文标题
通过功能化屈曲BI-III单层/al $ _ {2} $ o $ $ $ _ {3} $引起的大间隙量子异常厅。
Large-gap quantum anomalous Hall states induced by functionalizing buckled Bi-III monolayer/Al$_{2}$O$_{3}$
论文作者
论文摘要
拓扑量子异常大厅（QAH）效果固有的手性边缘模式是当代冷凝物研究的关键主题，目的是针对未来的量子技术和Spintronics中的应用。较大的拓扑间隙对于防止热波动，从而实现更高的工作温度至关重要。从第一原则计算中，我们提出了Al $ _ {2} $ o $ _ {3} $作为由BI和组III元素组成的原子单层的理想基板，其中可以实现大间隙量子旋转厅效应。然后，用氮的额外半疗法表明，拓扑相过渡到大间隙QAH绝缘子。通过有效的紧密结合建模，我们证明了BI-III单层/Al $ _ {2} $ o $ $ _ {3} $由$ p_ {x}，p_ {y} $ orbitals主导，具有属于$ p_z $ orbital的贡献。 Zeeman分裂引起的拓扑相变为QAH，在该分裂中，非对角线旋转交换不起作用。有效的模型分析承诺实用程序远远超出了BI-III单层/Al $ _ {2} $ o $ $ _ {3} $，因为它通常适用于由$ p_ {x}主导的系统，p_ {y} $ orbitals，带有$γ$的频带反转。
Chiral edge modes inherent to the topological quantum anomalous Hall (QAH) effect are a pivotal topic of contemporary condensed matter research aiming at future quantum technology and application in spintronics. A large topological gap is vital to protecting against thermal fluctuations and thus enabling a higher operating temperature. From first-principle calculations, we propose Al$_{2}$O$_{3}$ as an ideal substrate for atomic monolayers consisting of Bi and group-III elements, in which a large-gap quantum spin Hall effect can be realized. Additional half-passivation with nitrogen then suggests a topological phase transition to a large-gap QAH insulator. By effective tight-binding modelling, we demonstrate that Bi-III monolayer/Al$_{2}$O$_{3}$ is dominated by $p_{x}, p_{y}$ orbitals, with subdominant $p_z$ orbital contributions. The topological phase transition into the QAH is induced by Zeeman splitting, where the off-diagonal spin exchange does not play a significant role. The effective model analysis promises utility far beyond Bi-III monolayer/Al$_{2}$O$_{3}$, as it should generically apply to systems dominated by $p_{x}, p_{y}$ orbitals with a band inversion at $Γ$.
