We present evidence of topological surface states in beta-Ag2Te through first-principles calculations and periodic quantum interference effect in single crystalline nanoribbon. Our first-principles calculations show that beta-Ag2Te is a topological insulator with a gapless Dirac cone with strong anisotropy. To experimentally probe the topological surface state, we synthesized high quality beta-Ag2Te nanoribbons and performed electron transport measurements. The coexistence of pronounced Aharonov-Bohm oscillations and weak Altshuler-Aronov-Spivak oscillations clearly demonstrates coherent electron transport around the perimeter of beta-Ag2Te nanoribbon and therefore the existence of metallic surface states, which is further supported by the temperature dependence of resistivity for beta-Ag2Te nanoribbons with different cross section areas. Highly anisotropic topological surface state of beta-Ag2Te suggests that the material is a promising material for fundamental study and future spintronic devices.
@article{arxiv.1204.3816,
title = {Beta-Ag2Te: A topological insulator with strong anisotropy},
author = {Azat Sulaev and Peng Ren and Bin Xia and Qing Hua Lin and Ting Yu and Caiyu Qiu and Shuang-Yuan Zhang and Ming-Yong Han and Zhi Peng Li and Wei Guang Zhu and Qingyu Wu and Yuan Ping Feng and Lei Shen and Shun-Qing Shen and Lan Wang},
journal= {arXiv preprint arXiv:1204.3816},
year = {2013}
}