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Probing Quantum Capacitance in a 3D Topological Insulator
D A Kozlov1,2,3, D Bauer3, J Ziegler3
1A. V. Rzhanov Institute of Semiconductor Physics, Novosibirsk 630090, Russia.
Physical Review Letters
|May 7, 2016
Summary
Quantum capacitance measurements directly probe the electronic states of strained mercury telluride (HgTe) 2D electron systems. This technique uniquely accesses the top surface, revealing its Landau level spectrum.
Area of Science:
- Condensed matter physics
- Materials science
Background:
- Two-dimensional electron systems (2DES) on strained HgTe exhibit Dirac-like electronic properties.
- Understanding the surface electronic states is crucial for novel electronic applications.
Purpose of the Study:
- To directly measure the electronic density of states of a 2DES on strained HgTe.
- To demonstrate capacitance measurements as a tool for probing topological surface states.
Main Methods:
- Quantum capacitance measurements were performed on strained HgTe.
- Magnetocapacitance oscillations were analyzed.
Main Results:
- Observed magnetocapacitance oscillations primarily probe the top surface of the 2DES.
- Capacitance measurements provide a method to selectively probe one topological surface.
Conclusions:
- Quantum capacitance is a powerful technique for characterizing 2D electron systems.
- The Landau level spectrum of the top surface can be reconstructed using this method.
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