Enhanced surface mobility and quantum oscillations in topological insulator Bi1.5Sb0.5Te1.7Se1.3 nanoflakes

• Published in: Applied physics letters Vol. 103; no. 16
• Main Authors: Hsiung, Te-Chih, Chen, Ding-Yuan, Zhao, Li, Lin, Yi-Hsin, Mou, Chung-Yu, Lee, Ting-Kuo, Wu, Maw-Kuen, Chen, Yang-Yuan
• Format: Journal Article
• Language: English
• Published: 14-10-2013
• Subjects: Channels; Insulators; Nanocomposites; Nanomaterials; Nanostructure; Oscillations; Topology; Transport
• ISSN: 0003-6951; 1077-3118; 1077-3118
• DOI: 10.1063/1.4826092

In this study, a series of Bi1.5Sb0.5Te1.7Se1.3 (BSTS) flakes 80-nm to 140-μm in thickness was fabricated to investigate their metallic surface states. We report the observation of surface-dominated transport in these topological insulator BSTS nanoflakes. The achievement of surface-dominated transport can be attributed to high surface mobility (∼3000 cm2/V s) and low bulk mobility (12 cm2/V s). Up to 90% of the total conductance, the surface channel was estimated based on the thickness dependence of electrical conductance and the result of the Shubnikov-de Hass oscillations in a 200-nm BSTS. The nature of nontrivial Dirac surface states was also confirmed by the weak anti-localization effect.