Modification of the Hybridization Gap by Twisted Stacking of Quintuple Layers in a Three-Dimensional Topological Insulator Thin Film
Changyuan Zhou , Dezhi Song , Yeping Jiang*, and Jun Zhang
Key Laboratory of Polar Materials and Devices, Department of Electronics, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
Abstract：Twisting the stacking of layered materials leads to rich new physics. A three-dimensional topological insulator film hosts two-dimensional gapless Dirac electrons on top and bottom surfaces, which, when the film is below some critical thickness, will hybridize and open a gap in the surface state structure. The hybridization gap can be tuned by various parameters such as film thickness and inversion symmetry, according to the literature. The three-dimensional strong topological insulator Bi(Sb)Se(Te) family has layered structures composed of quintuple layers (QLs) stacked together by van der Waals interaction. Here we successfully grow twistedly stacked Sb$_{2}$Te$_{3}$ QLs and investigate the effect of twist angels on the hybridization gaps below the thickness limit. It is found that the hybridization gap can be tuned for films of three QLs, which may lead to quantum spin Hall states. Signatures of gap-closing are found in 3-QL films. The successful in situ application of this approach opens a new route to search for exotic physics in topological insulators.
. [J]. 中国物理快报, 2021, 38(5): 57307-057307.
Changyuan Zhou , Dezhi Song , Yeping Jiang, and Jun Zhang . Modification of the Hybridization Gap by Twisted Stacking of Quintuple Layers in a Three-Dimensional Topological Insulator Thin Film. Chin. Phys. Lett., 2021, 38(5): 57307-057307.
2021, Vol. 38 
