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

Te-Chih Hsiung, Ding-Yuan Chen, Li Zhao, Yi-Hsin Lin, Chung-Yu Mou, Ting-Kuo Lee, Maw-Kuen Wu, Yang-Yuan Chen
2013 Applied Physics Letters  
In this study, a series of Bi 1.5 Sb 0.5 Te 1.7 Se 1.3 (BSTS) flakes 80-nm to 140-lm 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 cm 2 /V s) and low bulk mobility (12 cm 2 /V s). Up to 90% of the total conductance, the surface channel was estimated based on the
more » ... 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. V C 2013 AIP Publishing LLC. [http://dx.
doi:10.1063/1.4826092 fatcat:3rvpbx4rxzb2naexawx4epw47q