Edge Channel Transmission through a Quantum Point Contact in the Two-Dimensional Topological Insulator Cadmium Arsenide.

Autor: Munyan S; Materials Department, University of California, Santa Barbara, California 93106-5050, United States., Rashidi A; Materials Department, University of California, Santa Barbara, California 93106-5050, United States., Lygo AC; Materials Department, University of California, Santa Barbara, California 93106-5050, United States., Kealhofer R; Materials Department, University of California, Santa Barbara, California 93106-5050, United States., Stemmer S; Materials Department, University of California, Santa Barbara, California 93106-5050, United States.
Jazyk: angličtina
Zdroj: Nano letters [Nano Lett] 2023 Jun 28; Vol. 23 (12), pp. 5648-5653. Date of Electronic Publication: 2023 Jun 12.
DOI: 10.1021/acs.nanolett.3c01263
Abstrakt: Cadmium arsenide (Cd 3 As 2 ) thin films feature a two-dimensional topological insulator (2D TI) phase for certain thicknesses, which theoretically hosts a set of counterpropagating helical edge states that are characteristic of a quantum spin Hall (QSH) insulator. In devices containing electrostatically defined junctions and for magnetic fields below a critical value, chiral edge modes of the quantum Hall effect can coexist with QSH-like edge modes. In this work, we use a quantum point contact (QPC) device to characterize edge modes in the 2D TI phase of Cd 3 As 2 and to understand how they can be controllably transmitted, which is important for use in future quantum interference devices. We investigate equilibration among both types of modes and find non-spin-selective equilibration. We also demonstrate the effect of the magnetic field on suppressing equilibration. We discuss the potential role of QSH-like modes in a transmission pathway that precludes full pinch-off.
Databáze: MEDLINE
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