Regensburg 2019 – scientific programme

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MA: Fachverband Magnetismus

MA 10: Poster Session: Topological Topics (joint session TT/MA)

MA 10.1: Poster

Monday, April 1, 2019, 15:00–18:30, Poster D

Helical edge state interferometry in a quantum spin Hall insulator — •Raul Stühler, André Kowalewski, Felix Reis, Johannes Weis, Jörg Schäfer, and Ralph Claessen — Physikalisches Institut (EP4) der Universität Würzburg, 97074 Würzburg, Germany

Since the discovery of the quantum spin Hall (QSH) effect, two-dimensional topological insulators (2D-TI) have constituted a promising system for spintronics and ballistic electronic transport. The latter property of 2D-TIs is based on exceptional quantum coherence of helical edge state electrons in the absence of time-reversal symmetry breaking. Notwithstanding, quantum interference between helical edge state electrons becomes relevant when a multitude of helical edge state pairs are being brought into direct proximity in a nano-constriction. Here we present the realization of a helical edge state nano-constriction embedded in the high-temperature 2D-TI bismuthene [1], formed by an anti-phase domain boundary of limited extent. Via STS, we prove quantum interference between counter propagating helical electrons and make use of an analogy to a Fabry-Pérot electronic resonator. Such interplay between quantum coherence and interference might be further exploited, e.g., as a controllable charge and spin current switch operated with gate voltages instead of magnetic fields [2].
F. Reis et al., Science 357, 287-290, (2017)

[2] P. Sternativo, F. Dolcini, Phys. Rev. B 89, 035415 (2014).