Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 54: Correlated Electrons: Heavy Fermions
TT 54.1: Vortrag
Mittwoch, 2. April 2014, 09:30–09:45, HSZ 204
Charge fluctuations in SmB6 — •Chul-hee Min1,2, Peter Lutz1,2, Sebastian Fiedler1,2, Boyoun Kang3, Beongki Cho3, Hyung-do Kim4, Hendrik Bentmann1,2, and Friedrich Reinert1,2 — 1Universität Würzburg, Experimentelle Physik VII & Röntgen Research Center for Complex Material Systems, 97074 Würzburg, Germany. — 2Karlsruhe Institut für Technologie, Gemeinschaftslabor für Nanoanalytik, 76021 Karlsruhe, Germany. — 3School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea. — 4Department of Physics and Astronomy, Center for Correlated Electron Systems, Institute for Basic Science, Seoul National University, Seoul 151-747, Republic of Korea.
Kondo insulators can have nontrivial Z2 topology because their energy gap opens at the Fermi energy (EF) by the hybridization between an odd parity- renormalized f band and an even parity- conduction d band. Samarium hexaboride (SmB6) is a promising candidate for the realization of such a correlated topological insulator. Here, we present the electronic structure of SmB6 by angle-resolved photoemission spectroscopy. Our spectra reveal that the bottom of the odd parity- d-f hybridized band at the X point gradually shifts from below to above EF with decreasing temperature. Moreover, by comparison with theoretical calculations, the signatures of nontrivial surface states are observed. Our results indicate that charge fluctuations play a major role during the gap evolution, and can be important in determining its Z2 topological indices.