Experimental evidences of topological surface states of β-Ag2Te

• Main Authors: Zhu, Weiguang, Sulaev, Azat, Ren, Peng, Xia, Bin, Lin, Qing Hua, Yu, Ting, Qiu, Caiyu, Zhang, Shuang-Yuan, Han, Ming-Yong, Li, Zhi Peng, Wu, Qingyu, Feng, Yuan Ping, Shen, Lei, Shen, Shun-Qing, Wang, Lan
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Science::Mathematics::Topology
• Online Access: https://hdl.handle.net/10356/95712; http://hdl.handle.net/10220/10063
• Institution: Nanyang Technological University

We present evidence of topological surface states in β-Ag2Te through first-principles calculations, periodic quantum interference effect and ambipolar electric field effect in single crystalline nanoribbon. Our first-principles calculations show that β-Ag2Te is a topological insulator with a gapless Dirac cone with strong anisotropy. To experimentally probe the topological surface state, we synthesized high quality β-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 β-Ag2Te nanoribbon and therefore the existence of topological surface states, which is further supported by the ambipolar electric field effect for devices fabricated by β-Ag2Te nanoribbons. The experimental evidences of topological surface states and the theoretically predicted anisotropic Dirac cone of β-Ag2Te suggest that the material may be a promising candidate of topological insulator for fundamental study and future spintronic devices.