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O: Fachverband Oberflächenphysik
O 10: Poster Session I: Topological insulators
O 10.3: Poster
Monday, March 1, 2021, 10:30–12:30, P
Lifting topological protection in a quantum spin Hall insulator — •Raul Stühler1, André Kowalewski1, Felix Reis1, Dimitri Jungblut1, Fernando Dominguez Tijero1, 2, Johannes Weis1, Benedikt Scharf1, Werner R. Hanke1, Gang Li3, Joerg Schaefer1, Ewelina M. Hankiewicz1, and Ralph Claessen1 — 1Universität Würzburg and Würzburg-Dresden Cluster of Excellence ct.qmat, Germany — 2Technische Universität Braunschweig, Germany — 3ShanghaiTech University, China
The recently discovered monolayer system bismuthene/SiC(0001) is a promising candidate for the realization of a room-temperature quantum spin Hall (QSH) effect [1]. As expected for a QSH insulator, the electronic edge channels do not show any signs of backscattering from kinky edge sections that would manifest in interference phenomena [2]. Notwithstanding, topological protection against defect scattering may become lifted when two helical edge channels are brought into direct proximity, resulting in quantum interference. By scanning tunneling microscopy we study phase-slip domain boundaries (DB) with limited longitudinal extent. By spectroscopic means we scrutinize quasi-particle interference along these one-dimensional topographic defects that points towards a linear electronic dispersion. We discuss our findings as possible quantum interference between coupled helical edge states formed in the vicinity of a DB, accompanied by lifting the topological protection via hybridization.
[1] F. Reis et al., Science 357, 287–290 (2017).
[2] R. Stühler et al., Nature Physics 16, 47–51 (2020).