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

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.

8 pages, 5 figures (main text) and 5 pages, 6 figures (Supplementary Material)

References in corpus (9)

• Topological Crystalline Insulators
• Quantum Hall Ferromagnetism in Graphene
• Robust spin-polarized midgap states at step edges of topological crystalline insulators
• Signatures of Dirac fermion-mediated magnetic order
• Interactions and magnetism in graphene boundary states
• A Systematic Investigation of the Coupling between One-Dimensional Edge States of a Topological Crystalline Insulator
• Landau level spectroscopy of PbSnSe topological crystalline insulator
• Bosonic field theory of tunable edge magnetism in graphene
• Fragility of the Dirac Cone Splitting in Topological Crystalline Insulator Heterostructures

Cited by in corpus (4)

• Spin-orbit insulating phase in SnTe cubic nanowires: consequences on the topological surface states
• Pentagonal nanowires from topological crystalline insulators: a platform for intrinsic core-shell nanowires and higher-order topology
• Probing chiral symmetry with a topological domain wall sensor
• Sensing the binding and unbinding of anyons at impurities