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arXiv · 2209.06837

Interaction effects in a 1D flat band at a topological crystalline step edge

Glenn Wagner·Souvik Das·Johannes Jung·Artem Odobesko·Felix Küster·Florian Keller·Jedrzej Korczak·Andrzej Szczerbakow·Tomasz Story·Stuart Parkin·Ronny Thomale·Titus Neupert·Matthias Bode·Paolo Sessi
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Abstract

Step edges of topological crystalline insulators can be viewed as predecessors of higher-order topology, as they embody one-dimensional edge channels embedded in an effective three-dimensional electronic vacuum emanating from the topological crystalline insulator. Using scanning tunneling microscopy and spectroscopy we investigate the behaviour of such edge channels in Pb$_{1-x}$Sn$_{x}$Se under doping. Once the energy position of the step edge is brought close to the Fermi level, we observe the opening of a correlation gap. The experimental results are rationalized in terms of interaction effects which are enhanced since the electronic density is collapsed to a one-dimensional channel. This constitutes a unique system to study how topology and many-body electronic effects intertwine, which we model theoretically through a Hartree-Fock analysis.

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Glenn Wagner, Souvik Das, Johannes Jung, Artem Odobesko, Felix Küster, Florian Keller, Jedrzej Korczak, Andrzej Szczerbakow, Tomasz Story, Stuart Parkin, Ronny Thomale, Titus Neupert, Matthias Bode, Paolo Sessi. 2022-09-14. Interaction effects in a 1D flat band at a topological crystalline step edge. https://doi.org/10.1021/acs.nanolett.2c03794

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