Topological crystalline insulator states in Pb1-xSnxSe

Summary, in English

Topological insulators are a class of quantum materials in which time-reversal symmetry, relativistic effects and an inverted band structure result in the occurrence of electronic metallic states on the surfaces of insulating bulk crystals. These helical states exhibit a Dirac-like energy dispersion across the bulk bandgap, and they are topologically protected. Recent theoretical results have suggested the existence of topological crystalline insulators (TCIs), a class of topological insulators in which crystalline symmetry replaces the role of time-reversal symmetry in ensuring topological protection(1,2). In this study we show that the narrow-gap semiconductor Pb1-xSnxSe is a TCI for x = 0.23. Temperature-dependent angle-resolved photoelectron spectroscopy demonstrates that the material undergoes a temperature-driven topological phase transition from a trivial insulator to a TCI. These experimental findings add a new class to the family of topological insulators, and we anticipate that they will lead to a considerable body of further research as well as detailed studies of topological phase transitions.

• Author: P. Dziawa; B. J. Kowalski; K. Dybko; R. Buczko; A. Szczerbakow; M. Szot; E. Lusakowska; Balasubramanian Thiagarajan; B. M. Wojek; M. H. Berntsen; O. Tjernberg; T. Story
• Department/s: MAX IV Laboratory
• Publishing year: 2012
• Language: English
• Pages: 1023-1027
• Publication/Series: Nature Materials
• Volume: 11
• Issue: 12
• Links: http://dx.doi.org/10.1038/NMAT3449
• Document type: Journal article
• Publisher: Nature Publishing Group
• Topic: Natural Sciences; Physical Sciences
• Status: Published
• ISBN/ISSN/Other: ISSN: 1476-4660