SKM 2021 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster Session III

HL 13.9: Poster

Tuesday, September 28, 2021, 13:30–16:30, P

Mobility spectrum analysis on three-dimensional topological insulator BiSbTeSe₂ — •Jimin Wang¹, Alexander Kurzendorfer¹, Lin Chen¹, Zhiwei Wang², Yoichi Ando², Yang Xu³, Ireneusz Miotkowski³, Yong P. Chen³, and Dieter Weiss¹ — ¹Institute of Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, German — ²Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937 Köln, Germany — ³Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA

We conducted mobility spectrum analysis on a high quality 3D topological insulator film of BiSbTeSe₂ to extract mobility µ, and carrier density n. Top and bottom gates were applied to tune the carrier density on top and bottom surfaces independently. At 1.5 K, when conduction is entirely dominated by the Dirac surface states, we always find two dominant conduction channels (top and bottom surfaces), with µ = 500−3000 cm²/(Vs), and n on the order of 10¹² cm⁻². However, at sufficiently high temperature (T= 85 K), when the bulk contributes, a third channel with maximum mobility µ ∼ 400 cm²/(Vs), and n on the order of 10¹¹−10¹³ cm⁻² opens. Our data show the feasibility of the method to analyze the different conduction channels in a topological insulator, being also promising for other similar material systems.