Unconventional transformation of spin Dirac phase across a topological quantum phase transition
Abstract
The topology of a topological material can be encoded in its surface states. These surface states can only be removed by a bulk topological quantum phase transition into a trivial phase. Here we use photoemission spectroscopy to image the formation of protected surface states in a topological insulator as we chemically tune the system through a topological transition. Surprisingly, we discover an exotic spinmomentum locked, gapped surface state in the trivial phase that shares many important properties with the actual topological surface state in anticipation of the change of topology. Using a spinresolved measurement, we show that apart from a surface bandgap these states develop spin textures similar to the topological surface states well before the transition. Our results provide a general paradigm for understanding how surface states in topological phases arise from a quantum phase transition and are suggestive for the future realization of Weyl arcs, condensed matter supersymmetry and other fascinating phenomena in the vicinity of a quantum criticality.
 Authors:

 Princeton Univ., Princeton, NJ (United States)
 Princeton Univ., Princeton, NJ (United States); Peking Univ., Beijing (China)
 Paul Scherrer Inst. (PSI), Villigen (Switzerland)
 Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ecole Polytechnique Fedeerale de Lausanne, Lausanne (Switzerland)
 Northeastern Univ., Boston, MA (United States)
 National Tsing Hua Univ., Hsinchu (Taiwan)
 National Tsing Hua Univ., Hsinchu (Taiwan); Academia Sinica, Taipei (Taiwan)
 National Univ. of Singapore (Singapore)
 Publication Date:
 Research Org.:
 SLAC National Accelerator Lab., Menlo Park, CA (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC)
 OSTI Identifier:
 1224062
 Grant/Contract Number:
 FG0207ER46352; AC0376SF00098; AC0376SF00515; FG0205ER46200
 Resource Type:
 Accepted Manuscript
 Journal Name:
 Nature Communications
 Additional Journal Information:
 Journal Volume: 6; Journal ID: ISSN 20411723
 Publisher:
 Nature Publishing Group
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; physical sciences; applied physics; condensed matter
Citation Formats
Xu, Su Yang, Neupane, Madhab, Belopolski, Ilya, Liu, Chang, Alidoust, Nasser, Bian, Guang, Jia, Shuang, Landolt, Gabriel, Slomski, Batosz, Dil, J. Hugo, Shibayev, Pavel P., Basak, Susmita, Chang, Tay Rong, Jeng, Horng Tay, Cava, Robert J., Lin, Hsin, Bansil, Arun, and Hasan, M. Zahid. Unconventional transformation of spin Dirac phase across a topological quantum phase transition. United States: N. p., 2015.
Web. doi:10.1038/ncomms7870.
Xu, Su Yang, Neupane, Madhab, Belopolski, Ilya, Liu, Chang, Alidoust, Nasser, Bian, Guang, Jia, Shuang, Landolt, Gabriel, Slomski, Batosz, Dil, J. Hugo, Shibayev, Pavel P., Basak, Susmita, Chang, Tay Rong, Jeng, Horng Tay, Cava, Robert J., Lin, Hsin, Bansil, Arun, & Hasan, M. Zahid. Unconventional transformation of spin Dirac phase across a topological quantum phase transition. United States. doi:10.1038/ncomms7870.
Xu, Su Yang, Neupane, Madhab, Belopolski, Ilya, Liu, Chang, Alidoust, Nasser, Bian, Guang, Jia, Shuang, Landolt, Gabriel, Slomski, Batosz, Dil, J. Hugo, Shibayev, Pavel P., Basak, Susmita, Chang, Tay Rong, Jeng, Horng Tay, Cava, Robert J., Lin, Hsin, Bansil, Arun, and Hasan, M. Zahid. Fri .
"Unconventional transformation of spin Dirac phase across a topological quantum phase transition". United States. doi:10.1038/ncomms7870. https://www.osti.gov/servlets/purl/1224062.
@article{osti_1224062,
title = {Unconventional transformation of spin Dirac phase across a topological quantum phase transition},
author = {Xu, Su Yang and Neupane, Madhab and Belopolski, Ilya and Liu, Chang and Alidoust, Nasser and Bian, Guang and Jia, Shuang and Landolt, Gabriel and Slomski, Batosz and Dil, J. Hugo and Shibayev, Pavel P. and Basak, Susmita and Chang, Tay Rong and Jeng, Horng Tay and Cava, Robert J. and Lin, Hsin and Bansil, Arun and Hasan, M. Zahid},
abstractNote = {The topology of a topological material can be encoded in its surface states. These surface states can only be removed by a bulk topological quantum phase transition into a trivial phase. Here we use photoemission spectroscopy to image the formation of protected surface states in a topological insulator as we chemically tune the system through a topological transition. Surprisingly, we discover an exotic spinmomentum locked, gapped surface state in the trivial phase that shares many important properties with the actual topological surface state in anticipation of the change of topology. Using a spinresolved measurement, we show that apart from a surface bandgap these states develop spin textures similar to the topological surface states well before the transition. Our results provide a general paradigm for understanding how surface states in topological phases arise from a quantum phase transition and are suggestive for the future realization of Weyl arcs, condensed matter supersymmetry and other fascinating phenomena in the vicinity of a quantum criticality.},
doi = {10.1038/ncomms7870},
journal = {Nature Communications},
number = ,
volume = 6,
place = {United States},
year = {2015},
month = {4}
}
Web of Science