Two-Dimensional-Dirac Surface States and Bulk Gap Probed via Quantum Capacitance in a Three-Dimensional Topological Insulator

• DOI: 10.1021/acs.nanolett.0c02733
• Publication Date: 2020-11-11T12:10:50Z
• Authors: Jimin Wang; Cosimo Gorini; Klaus Richter; Zhiwei Wang; Yoichi Ando; Dieter Weiss
• Keywords: Topological insulator; Surface States; Landau quantization; Density of states

BiSbTeSe$_2$ is a 3D topological insulator (3D-TI) with Dirac type surface states and low bulk carrier density, as donors acceptors compensate each other. Dominating temperature transport in this material heralded by Shubnikov-de Haas oscillations the quantum Hall effect. Here, we experimentally probe model electronic density of (DOS) thin layers capacitance experiments both without quantizing magnetic fields. By probing lowest Landau levels, show that large fraction electrons filled via field effect into system ends up (localized) appears background DOS. The surprisingly strong dependence such DOS can be traced back to Coulomb interactions. Our results point at coexistence intimate coupling many-body phase (a glass) 3D-TIs.