Recently, a new type of second-order topological insulator has been theoretically proposed by introducing an in-plane Zeeman field into the Kane-Mele model in the two-dimensional honeycomb lattice. A pair of topological corner states arise at the corners with obtuse angles of an isolated diamond-shaped flake. To probe the corner states, we study their transport properties by attaching two leads to the system. Dressed by incoming electrons, the dynamic corner state is very different from its static counterpart. Resonant tunneling through the dressed corner state can occur by tuning the in-plane Zeeman field. At the resonance, the pair of spatially well separated and highly localized corner states can form a dimer state, whose wavefunction extends almost the entire bulk of the diamond-shaped flake. By varying the Zeeman field strength, multiple resonant tunneling events are mediated by the same dimer state. This re-entrance effect can be understood by a simple model. These findings extend our understanding of dynamic aspects of the second-order topological corner states.

近来，通过将平面塞曼场引入二维蜂窝格子的凯恩-梅勒模型中，理论上提出了一种新型的二阶拓扑绝缘子。一对拓扑拐角状态以孤立的菱形薄片的钝角出现在拐角处。为了探测拐角状态，我们通过将两条引线连接到系统来研究它们的传输特性。由入射电子修饰，动态转角状态与静态对应状态有很大不同。通过调整面内塞曼场，可以发生穿过修整的角状态的共振隧穿。在共振时，一对空间上分离良好且高度局部化的拐角状态可以形成二聚体状态，其波函数几乎延伸了整个菱形薄片的大部分。通过改变塞曼场强，多个共振隧穿事件是由相同的二聚体状态介导的。可以通过一个简单的模型来了解这种重新进入的效果。这些发现扩展了我们对二阶拓扑角状态的动态方面的理解。