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Observation of a topological crystalline insulator phase and topological phase transition in Pb1−xSnxTe
- Publication Year :
- 2012
-
Abstract
- A topological insulator protected by time-reversal symmetry is realized via spin-orbit interaction-driven band inversion. The topological phase in the Bi1-xSbx system is due to an odd number of band inversions. A related spin-orbit system, the Pb1-xSnxTe, has long been known to contain an even number of inversions based on band theory. Here we experimentally investigate the possibility of a mirror symmetry-protected topological crystalline insulator phase in the Pb1-xSnxTe class of materials that has been theoretically predicted to exist in its end compound SnTe. Our experimental results show that at a finite Pb composition above the topological inversion phase transition, the surface exhibits even number of spin-polarized Dirac cone states revealing mirror-protected topological order distinct from that observed in Bi1-xSbx. Our observation of the spin-polarized Dirac surface states in the inverted Pb1-xSnxTe and their absence in the non-inverted compounds related via a topological phase transition provide the experimental groundwork for opening the research on novel topological order in quantum devices.
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.dedup.wf.001..1b67ea787b9cc64737c3aec012942412