RF compressibility of topological surface and interface states in metal-hBN-Bi2Se3 capacitors

Autor:	Inhofer, Andreas, Wilde, Taylor, Duffy, Jack, Boukhicha, Mohamed, Palomo, José, Watanabe, Kenji, Taniguchi, Takashi, Berroir, Jean-Marc, Fève, Gwendal, Bocquillon, Erwann, Plaçais, Bernard, Assaf, Badih A.
Rok vydání:	2019
Předmět:	Condensed Matter - Mesoscale and Nanoscale Physics Condensed Matter - Materials Science
Druh dokumentu:	Working Paper
DOI:	10.1088/2515-7639/ab383c
Popis:	The topological state that emerges at the surface of a topological insulator (TI) and at the TI-substrate interface are studied in metal-hBN-Bi2Se3 capacitors. By measuring the RF admittance of the capacitors versus gate voltage, we extract the compressibility of the Dirac state located at a gated TI surface. We show that even in the presence of an ungated surface that hosts a trivial electron accumulation layer, the other gated surface always exhibits an ambipolar effect in the quantum capacitance. We succeed in determining the velocity of surface Dirac fermions in two devices, one with a passivated surface and the other with a free surface that hosts trivial states. Our results demonstrate the potential of RF quantum capacitance techniques to probe surface states of systems in the presence of a parasitic density-of-states. Comment: J. Phys.: Mater. Focus on Topological Matter
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1908.05270 Zobrazit plný text záznamu View this record from Arxiv