Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 82: Topological Insulators II (joint session TT/MA)

TT 82.2: Vortrag

Donnerstag, 15. März 2018, 09:45–10:00, A 053

Quantum capacitance measurements in BiSbTeSe₂ 3D topological insulators — •Jimin Wang¹, Zhiwei Wang², Yoichi Ando², and Dieter Weiss¹ — ¹Institute for Experimental and Applied Physics, University of Regensburg, D-93040 Regensburg, Germany — ²Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany

We conducted low temperature quantum capacitance measurements in high quality bulk-insulating 3D topological insulators BiSbTeSe₂ flakes, with h-BN as protective capping layers. The density of states extracted from the gate voltage dependence of the quantum capacitance is asymmetric with respect its minimum, indicating a partly nonlinear energy dispersion. Our results can be well fitted using a linear dispersion with superimposed parabolic contributions, which are in agreement with literature [1, 2]. At magnetic fields higher than 10 T, we clearly resolve the zeroth Landau level, which can be observed at least up to 85 K. Due to impurity broadening, higher Landau levels cannot be resolved.
A. A. Taskin, et al., PRL 107, 016801 (2011)
T. Arakane et al., Nat. Commun. 3:636 (2012)