Observation of a topological crystalline insulator phase and topological phase transition in Pb1-xSnxTe
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.
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Xu, S.-Y., Liu, C., Alidoust, N., Neupane, M., Qian, D., Belopolski, I., Denlinger, J. D., Wang, Y. J., Lin, H., Wray, L. A., Landolt, G., Slomski, B., Dil, J. H., Marcinkova, A., Morosan, E., Gibson, Q., Sankar, R., Chou, F. C., Cava, R. J., et al. (2012). Observation of a topological crystalline insulator phase and topological phase transition in Pb1-xSnxTe. Nature Communications, 3, Article 1192. https://doi.org/10.1038/ncomms2191
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WOS:000315992100027
2012
3
1192
REVIEWED
OTHER