Gate-tuned quantum oscillations of topological surface states in β-Ag2Te

• Main Authors: Sulaev, Azat, Zhu, Weiguang, Teo, Kie Leong, Wang, Lan
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2015
• Subjects: DRNTU::Science::Physics::Atomic physics::Quantum theory
• Online Access: https://hdl.handle.net/10356/106923; http://hdl.handle.net/10220/25158
• Institution: Nanyang Technological University

We report the strong experimental evidence of the existence of topological surface states with large electric field tunability and mobility in β-Ag2Te. Pronounced 2D Shubnikov-de Haas oscillations have been observed in β-Ag2Te nanoplates. A Berry phase is determined to be near π using the Landau level fan diagram for a relatively wide nanoplate while the largest electric field ambipolar effect in topological insulator so far (~2500%) is observed in a narrow nanoplate. The π Berry phase and the evolution of quantum oscillations with gate voltage (Vg) in the nanoplates strongly indicate the presence of topological surface states in β-Ag2Te. Moreover, the mobility of the narrow Ag2Te nanoplate is about several thousand cm2s−1V−1. Our results suggest that β-Ag2Te has the potential to become an important material in the investigation of topological insulators.