A topological crystalline insulator (TCI) phase via topological phase transition and crystalline mirror symmetry

Autor: Xu, Su-Yang, Liu, Chang, Alidoust, Nasser, 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., Bansil, A., Hasan, M. Z.
Rok vydání: 2012
Předmět:
Zdroj: Suyang Xu et.al., Nature Communications 3, 1192 (2012)
Druh dokumentu: Working Paper
DOI: 10.1038/ncomms2191
Popis: A Z2 topological insulator protected by time-reversal symmetry is realized via spin-orbit interaction driven band inversion. For example, the topological phase in the Bi-Sb system is due to an odd number of band inversions. A related spin-orbit system, the (Pb/Sn)Te class, has 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 (Pb/Sn)Te class of materials which has been theoretically predicted to exist in its non-alloyed version. 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 (as opposed to odd as observed in Bi-Sb alloy or Bi2Se3) revealing mirror protected topological order distinct from that observed in Bi-Sb or Bi2Se3. Our observation of the spin-polarized Dirac surface states in the inverted (Pb/Sn)Te and their absence in the non-inverted compounds related via a topological phase transition (spin-orbit induced band inversion type) provide the experimental groundwork for opening the research on novel topological order in future quantum devices.
Comment: 45 pages, 17 Figures, Earlier observation reported at http://xxx.lanl.gov/abs/1206.2088 (11th June, 2012); Expanded ver.(17 Figs) accepted for publication (in press) in Nature Communications (2012)
Databáze: arXiv
Externí odkaz: