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Gapped Surface States in a Strong-Topological-Insulator Material

Author(s): Weber, Andrew P.; Gibson, Quinn D.; Ji, Huiwen; Caruso, Anthony N.; Fedorov, A.V.; et al

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Abstract: A three-dimensional strong-topological insulator or semimetal hosts topological surface states which are often said to be gapless so long as time-reversal symmetry is preserved. This narrative can be mistaken when surface state degeneracies occur away from time-reversal-invariant momenta. The mirror invariance of the system then becomes essential in protecting the existence of a surface Fermi surface. Here we show that such a case exists in the strong-topological-semimetal Bi4Se3. Angle-resolved photoemission spectroscopy and ab initio calculations reveal partial gapping of surface bands on the Bi2Se3 termination of Bi4Se3(111), where an 85 meV gap along Γ¯K¯ closes to zero toward the mirror-invariant Γ¯M¯ azimuth. The gap opening is attributed to an interband spin-orbit interaction that mixes states of opposite spin helicity. © 2015 American Physical Society.
Publication Date: Jun-2015
Electronic Publication Date: 23-Jun-2015
Citation: Weber, Andrew P., Gibson, Quinn D., Ji, Huiwen, Caruso, Anthony N., Fedorov, A.V., Cava, Robert J., Valla, Tonica (2015). Gapped Surface States in a Strong-Topological-Insulator Material. Physical Review Letters, 114 (25), 10.1103/PhysRevLett.114.256401
DOI: doi:10.1103/PhysRevLett.114.256401
ISSN: 0031-9007
EISSN: 1079-7114
Pages: 114.25:256401-1 - 258401-5
Type of Material: Journal Article
Journal/Proceeding Title: Physical Review Letters
Version: Final published version. This is an open access article.
Notes: Physical Review Letters. Volume 114, Issue 25, 23 June 2015, Article number 256401.

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