Wang, Jimin and Gorini, Cosimo and Richter, Klaus and Wang, Zhiwei and Ando, Yoichi and Weiss, Dieter (2020) Two-Dimensional-Dirac Surface States and Bulk Gap Probed via Quantum Capacitance in a Three-Dimensional Topological Insulator. NANO LETTERS, 20 (12). pp. 8493-8499. ISSN 1530-6984, 1530-6992
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BiSbTeSe2 is a 3D topological insulator (3D-TI) with Dirac type surface states and low bulk carrier density, as donors and acceptors compensate each other. Dominating low-temperature surface transport in this material is heralded by Shubnikov-de Haas oscillations and the quantum Hall effect. Here, we experimentally probe and model the electronic density of states (DOS) in thin layers of BiSbTeSe2 by capacitance experiments both without and in quantizing magnetic fields. By probing the lowest Landau levels, we show that a large fraction of the electrons filled via field effect into the system ends up in (localized) bulk states and appears as a background DOS. The surprisingly strong temperature dependence of such background DOS can be traced back to Coulomb interactions. Our results point at the coexistence and intimate coupling of Dirac surface states with a bulk many-body phase (a Coulomb glass) in 3D-TIs.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ELECTRON; DENSITY; compensated 3D-topological insulator; BiSbTeSe2; quantum capacitance; Landau quantization; thermodynamic density of states; Coulomb glass |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics Physics > Institute of Theroretical Physics > Chair Professor Richter > Group Klaus Richter Physics > Institute of Experimental and Applied Physics Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Dieter Weiss |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 05 Mar 2021 08:05 |
| Last Modified: | 05 Mar 2021 08:05 |
| URI: | https://pred.uni-regensburg.de/id/eprint/43154 |
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