Interaction Effects in a 1D Flat Band at a Topological Crystalline Step Edge

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...

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Bibliographic Details
Published in:Nano letters 2023-04, Vol.23 (7), p.2476-2482
Main Authors: Wagner, Glenn, Das, Souvik, Jung, Johannes, Odobesko, Artem, Küster, Felix, Keller, Florian, Korczak, Jedrzej, Szczerbakow, Andrzej, Story, Tomasz, Parkin, Stuart S. P., Thomale, Ronny, Neupert, Titus, Bode, Matthias, Sessi, Paolo
Format: Article
Language:English
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Letter
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Summary: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 behavior of such edge channels in Pb1–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.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.2c03794