Topological nature of step edge states on the surface of topological crystalline insulator Pb${}_{0.7}$Sn${}_{0.3}$Se

Abstract

In addition to novel surface states, topological insulators can also exhibit robust gapless states at crystalline defects. Step edges constitute a class of common defects on the surface of crystals. In this work we establish the topological nature of one-dimensional (1D) bound states localized at step edges of the [001] surface of a topological crystalline insulator (TCI) Pb${}_{0.7}$Sn${}_{0.3}$Se, both theoretically and experimentally. We show that the topological stability of the step edge states arises from an emergent particle-hole symmetry of the surface low-energy physics, and demonstrate the experimental signatures of the particle-hole symmetry breaking. We also reveal the effects of an external magnetic field on the 1D bound states. Our work suggests the possibility of similar topological step edge modes in other topological materials with a rocks-salt structure.

arXiv comment8+6 pages, 6 figures, references and acknowledgements updated

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Cited by in corpus (9)

• Partial lattice defects in higher order topological insulators
• Experimental search for the origin of low-energy modes in topological materials
• Topological properties of multilayers and surface steps in the SnTe material class
• Observation of Weyl and Dirac fermions at smooth topological Volkov-Pankratov heterojunctions
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• Interaction effects in a 1D flat band at a topological crystalline step edge
• Topological electronic structure of twin boundaries and twinning superlattices in the SnTe material class
• Proximity-Induced Superconductivity in a Topological Crystalline Insulator
• Chiral $p-$wave superconductivity in Pb${}_{1-x}$Sn${}_x$Te: signatures from bound-state spectra and wavefunctions