"Epitaxial growth of ultraflat stanene with topological band inversion"

Jialiang Deng : Bingyu Xia, Xiaochuan Ma, Haoqi Chen, Huan Shan, Xiaofang Zhai, Bin Li, Aidi Zhao , Yong Xu , Wenhui Duan, Shou-Cheng Zhang, Bing Wang and J. G. Hou; Nature Materials, 11/05/18.

Additional Authors: Bingyu Xia, Xiaochuan Ma, Haoqi Chen, Huan Shan, Xiaofang Zhai, Bin Li, Aidi Zhao , Yong Xu , Wenhui Duan, Shou-Cheng Zhang, Bing Wang and J. G. Hou

Abstract:

Two-dimensional (2D) topological materials, including quantum spin/anomalous Hall insulators, have attracted intense research efforts owing to their promise for applications ranging from low-power electronics and high-performance thermoelectrics to fault-tolerant quantum computation. One key challenge is to fabricate topological materials with a large energy gap for room-temperature use. Stanene—the tin counterpart of graphene—is a promising material candidate distinguished by its tunable topological states and sizeable bandgap. Recent experiments have successfully fabricated stanene, but none of them have yet observed topological states. Here we demonstrate the growth of high-quality stanene on Cu(111) by low-temperature molecular beam epitaxy. Importantly, we discovered an unusually ultraflat stanene showing an in-plane s–p band inversion together with a spin–orbit-coupling-induced topological gap (~0.3 eV) at the Γ point, which represents a foremost group-IV ultraflat graphene-like material displaying topological features in experiment. The finding of ultraflat stanene opens opportunities for exploring two-dimensional topological physics and device applications.