Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Light-Induced Quantum Anomalous Hall Effect on the 2D Surfaces of 3D Topological Insulators
Advanced Science ( IF 14.3 ) Pub Date : 2021-07-02 , DOI: 10.1002/advs.202101508 Haowei Xu 1 , Jian Zhou 1 , Ju Li 1, 2
Advanced Science ( IF 14.3 ) Pub Date : 2021-07-02 , DOI: 10.1002/advs.202101508 Haowei Xu 1 , Jian Zhou 1 , Ju Li 1, 2
Affiliation
|
Quantum anomalous Hall (QAH) effect generates quantized electric charge Hall conductance without external magnetic field. It requires both nontrivial band topology and time-reversal symmetry (TRS) breaking. In most cases, one can break the TRS of time-reversal invariant topological materials to yield QAH effect, which is essentially a topological phase transition. However, conventional topological phase transition induced by external field/stimulus usually needs a route along which the bandgap closes and reopens. Hence, the transition occurs only when the magnitude of field/stimulus is larger than a critical value. In this work the authors propose that using gapless systems, the transition can happen at an arbitrarily weak (but finite) external field strength. For such an unconventional topological phase transition, the bandgap closing is guaranteed by bulk-edge correspondence and symmetries, while the bandgap reopening is induced by external fields. This concept is demonstrated on the 2D surface states of 3D topological insulators like Bi2Se3, which become 2D QAH insulators once a circularly polarized light is turned on, according to the Floquet time crystal theory. The sign of quantized Chern number can be controlled via the chirality of the light. This provides a convenient and dynamic approach to trigger topological phase transitions and create QAH insulators.
中文翻译：
3D 拓扑绝缘体 2D 表面上的光致量子反常霍尔效应
量子反常霍尔（QAH）效应无需外部磁场即可产生量子化电荷霍尔电导。它需要非平凡的带拓扑和时间反转对称性（TRS）破缺。在大多数情况下，人们可以打破时间反转不变拓扑材料的TRS来产生QAH效应，这本质上是一种拓扑相变。然而，由外部场/刺激引起的传统拓扑相变通常需要一条带隙关闭和重新打开的路径。因此，仅当场/刺激的幅度大于临界值时才会发生转变。在这项工作中，作者提出，使用无间隙系统，转变可以在任意弱（但有限）的外部场强下发生。对于这种非常规的拓扑相变，带隙闭合是由体边对应和对称性保证的，而带隙重新打开是由外部场引起的。这个概念在 Bi 2 Se 3等 3D 拓扑绝缘体的 2D 表面态上得到了证明，根据 Floquet 时间晶体理论，一旦打开圆偏振光，这些绝缘体就会变成 2D QAH 绝缘体。量子化陈数的符号可以通过光的手性来控制。这提供了一种方便且动态的方法来触发拓扑相变并创建 QAH 绝缘体。
更新日期：2021-09-09
中文翻译：
3D 拓扑绝缘体 2D 表面上的光致量子反常霍尔效应
量子反常霍尔（QAH）效应无需外部磁场即可产生量子化电荷霍尔电导。它需要非平凡的带拓扑和时间反转对称性（TRS）破缺。在大多数情况下，人们可以打破时间反转不变拓扑材料的TRS来产生QAH效应，这本质上是一种拓扑相变。然而，由外部场/刺激引起的传统拓扑相变通常需要一条带隙关闭和重新打开的路径。因此，仅当场/刺激的幅度大于临界值时才会发生转变。在这项工作中，作者提出，使用无间隙系统，转变可以在任意弱（但有限）的外部场强下发生。对于这种非常规的拓扑相变，带隙闭合是由体边对应和对称性保证的，而带隙重新打开是由外部场引起的。这个概念在 Bi 2 Se 3等 3D 拓扑绝缘体的 2D 表面态上得到了证明，根据 Floquet 时间晶体理论，一旦打开圆偏振光，这些绝缘体就会变成 2D QAH 绝缘体。量子化陈数的符号可以通过光的手性来控制。这提供了一种方便且动态的方法来触发拓扑相变并创建 QAH 绝缘体。
京公网安备 11010802027423号