Surface reactivity is important in modifying the physical and chemical properties of surface sensitive materials, such as the topological insulators (TIs). Even though many studies addressing the reactivity of TIs towards external gases have been reported, it is still under heavy debate whether and how the topological insulators react with H2O. Here, we employ scanning tunneling microscopy (STM) to directly probe the surface reaction of Bi2Te3 towards H2O. Surprisingly, it is found that only the top quintuple layer is reactive to H2O, resulting in a hydrated Bi bilayer as well as some Bi islands, which passivate the surface and prevent from the subsequent reaction. A reaction mechanism is proposed with H2Te and hydrated Bi as the products. Unexpectedly, our study indicates the reaction with water is intrinsic and not dependent on any surface defects. Since water inevitably exists, these findings provide key information when considering the reactions of Bi2Te3 with residual gases or atmosphere.
@article{arxiv.1606.07999,
title = {Real-space characterization of reactivity towards water at Bi2Te3(111) surface},
author = {Kai-Wen Zhang and Ding Ding and Chao-Long Yang and Yuan Gan and Shichao Li and Wen-Kai Huang and Ye-Heng Song and Zhen-Yu Jia and Xiang-Bing Li and Zihua Zhu and Jinsheng Wen and Mingshu Chen and Shao-Chun Li},
journal= {arXiv preprint arXiv:1606.07999},
year = {2016}
}
Comments
17 pages, 5 figures, accepted, Phys. Rev. B (2016)