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Nonmagnetic band gap at the Dirac point of the magnetic topological insulator (Bi1-xMnx)2Se3

Citace:
SÁNCHEZ-BARRIGA, J., VARYKHALOV, A., SPRINGHOLZ, G., STEINER, H., KIRCHSCHLAGER, R., BAUER, G., CAHA, O., SCHIERLE, E., WESCHKE, E., UNAL, A., VALENCIA, S., DUNST, M., BRAUN, J., EBERT, H., MINÁR, J., GOLIAS, E., YASHINA, L., NEY, A., HOLÝ, V., RADER, O. Nonmagnetic band gap at the Dirac point of the magnetic topological insulator (Bi1-xMnx)2Se3. NATURE COMMUNICATIONS, 2016, roč. 7, č. FEB 2016, s. 1-10. ISSN: 2041-1723
Druh: ČLÁNEK
Jazyk publikace: eng
Anglický název: Nonmagnetic band gap at the Dirac point of the magnetic topological insulator (Bi1-xMnx)2Se3
Rok vydání: 2016
Autoři: J. Sánchez-Barriga , A. Varykhalov , G. Springholz , H. Steiner , R. Kirchschlager , G. Bauer , O. Caha , E. Schierle , E. Weschke , A.A. Unal , S. Valencia , M. Dunst , J. Braun , H. Ebert , Doc.Dr. Jan Minár , E. Golias , L.V. Yashina , A. Ney , V. Holý , O. Rader
Abstrakt EN: Magnetic doping is expected to open a band gap at the Dirac point of topological insulators by breaking time-reversal symmetry and to enable novel topological phases. Epitaxial (Bi1 xMnx)2 Se3 is a prototypical magnetic topological insulator with a pronounced surface band gap of B100 meV. We show that this gap is neither due to ferromagnetic order in the bulk or at the surface nor to the local magnetic moment of the Mn, making the system unsuitable for realizing the novel phases. We further show that Mn doping does not affect the inverted bulk band gap and the system remains topologically nontrivial. We suggest that strong resonant scattering processes cause the gap at the Dirac point and support this by the observation of in-gap states using resonant photoemission. Our findings establish a mechanism for gap opening in topological surface states which challenges the currently known conditions for topological protection.
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