近日，美国加州大学的Michael F.Crommie及其研究团队与美国普渡大学的Tiancong Zhu等人合作并取得一项新进展。经过不懈努力，他们实现莫尔量子反常霍尔绝缘体中手性界面态的操纵。相关研究成果已于
该研究团队成功地在由扭曲单层-双层石墨烯制成的，相互作用驱动量子反常霍尔绝缘体中操纵了陈域，并观察了不同域边界处的手性界面态。通过调整载流子浓度，他们成功稳定了具有相反陈数的邻近域，从而构建出无需任何结构边界的拓扑界面。
这一创新使得研究人员能够利用扫描隧道显微镜直接成像手性界面态的波函数。随后的理论分析不仅证实了观察到的界面态的手性性质，还帮助他们确定了相邻陈域的谷极化反演的特征长度尺度。
据悉，由堆叠的二维材料制成的莫尔系统具有关联和拓扑态，可以通过施加栅极电压进行电气控制。一种常见的拓扑态是陈绝缘体，它表现出量子反常霍尔效应。
附：英文原文
Title: Manipulation of chiral interface states in a moiré quantum anomalous Hall insulator
Author: Zhang, Canxun, Zhu, Tiancong, Kahn, Salman, Soejima, Tomohiro, Watanabe, Kenji, Taniguchi, Takashi, Zettl, Alex, Wang, Feng, Zaletel, Michael P., Crommie, Michael F.
Issue&Volume: 2024-03-13
Abstract: Moiré systems made from stacked two-dimensional materials host correlated and topological states that can be electrically controlled with applied gate voltages. One prevalent form of topological state that can occur are Chern insulators that display a quantum anomalous Hall effect. Here we manipulate Chern domains in an interaction-driven quantum anomalous Hall insulator made from twisted monolayer–bilayer graphene and observe chiral interface states at the boundary between different domains. By tuning the carrier concentration, we stabilize neighbouring domains of opposite Chern number that then provide topological interfaces devoid of any structural boundaries. This allows the wavefunction of chiral interface states to be directly imaged using a scanning tunnelling microscope. Our theoretical analysis confirms the chiral nature of observed interface states and allows us to determine the characteristic length scale of valley polarization reversal across neighbouring Chern domains.
DOI: 10.1038/s41567-024-02444-w
Source: https://www.nature.com/articles/s41567-024-02444-w