Visualizing the in-Gap States in Domain Boundaries of Ultra-Thin Topological Insulator Films
Jun Zhang1, Junbo Cheng1, Shuaihua Ji2, and Yeping Jiang1*
1Key Laboratory of Polar Materials and Devices, Department of Electronic, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China 2State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
Abstract：Ultra-thin topological insulators provide a platform for realizing many exotic phenomena such as the quantum spin Hall effect, and quantum anomalous Hall effect. These effects or states are characterized by quantized transport behavior of edge states. Experimentally, although these states have been realized in various systems, the temperature for the edge states to be the dominating channel in transport is extremely low, contrary to the fact that the bulk gap is usually in the order of a few tens of milli-electron volts. There must be other in-gap conduction channels that do not freeze out until a much lower temperature. Here we grow ultra-thin topological insulator Bi$_{2}$Te$_{3}$ and Sb$_{2}$Te$_{3}$ films by molecular beam epitaxy and investigate the structures of domain boundaries in these films. By scanning tunneling microscopy and spectroscopy we find that the domain boundaries with large rotation angles have pronounced in-gap bound states, through which one-dimensional conduction channels are suggested to form, as visualized by spatially resolved spectroscopy. Our work indicates the critical role played by domain boundaries in degrading the transport properties.
. [J]. 中国物理快报, 2021, 38(7): 77301-.
Jun Zhang, Junbo Cheng, Shuaihua Ji, and Yeping Jiang. Visualizing the in-Gap States in Domain Boundaries of Ultra-Thin Topological Insulator Films. Chin. Phys. Lett., 2021, 38(7): 77301-.
2021, Vol. 38 
