论文标题
弱二阶拓扑绝缘子的螺旋铰链状态的稳健性
Robustness of Helical Hinge States of Weak Second-Order Topological Insulators
论文作者
论文摘要
研究了针对疾病的三维弱二阶I硫酸（WSOTI）的螺旋铰链状态的稳健性。纯WSOTI是从弱$ \ Mathbb {z} _2 $一阶拓扑绝缘子通过表面频带反转获得的。 WSOTI中的散装状态和表面状态都被覆盖，并且间隙山谷锁紧的螺旋铰链状态受到地表谷地的数字拓扑保护。在存在弱疾病的情况下，螺旋铰链状态对疾病具有鲁棒性，而量化状态的量化导致由于valley间的散射而脆弱。随着疾病的增加，系统会经历一系列量子相变：从WSOTI到弱的一阶拓扑绝缘子，然后再到扩散金属，最后到安德森绝缘子。因此，我们的结果将WSOTI阶段完全确定为真正的物质状态，并为二阶Valleytronics打开了一扇门，该阶段使人们能够通过螺旋铰链状态控制山谷的自由度。
Robustness of helical hinge states of three-dimensional weak second-order topological i sulators (WSOTIs) against disorders is studied. The pure WSOTI is obtained from a weak $\mathbb{Z}_2$ first-order topological insulator through a surface band inversion. Both bulk states and surface states in the WSOTI are gapped, and in-gap valley-momentum locked helical hinge states are topologically protected by the surface valley-Chern number. In the presence of weak disorders, helical hinge states are robust against disorders while the quantized conductance of the states is fragile due to the inter-valley scattering. As disorder increases, the system undergoes a series of quantum phase transitions: from the WSOTI to the weak first-order topological insulator, then to a diffusive metal and finally to an Anderson insulator. Our results thus fully establish the WSOTI phase as a genuine state of matters and open a door for the second-order valleytronics that allows one to control the valley degree of freedom through helical hinge states.
