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Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 48: Transport: Topological Insulators I (organized by TT)

TT 48.4: Vortrag

Dienstag, 1. April 2014, 14:45–15:00, HSZ 304

Photoemission investigation of the predicted topological Kondo insulator behavior of SmB6 — •Peter Hlawenka1, Emile Rienks1, Konrad Siemensmeyer1, Eugen Weschke1, Andrei Varykhalov1, Natalya Shitsevalova2, Slavomir Gabani3, Karol Flachbart3, and Oliver Rader11Helmholtz-Zentrum Berlin — 2Institute for Problems of Material Science, Kiev, Ukraine — 3IEP, Slovak Academy of Science, Kosice

The system SmB6 is known for its unusual resistivity which increases exponentially with decreasing temperature and saturates below 3 K [1]. This has recently been attributed to topological-Kondo-insulator behavior where a topological surface state is created by Sm4f-5d hybridization and is responsible for the transport [2]. The local-density-approximation + Gutzwiller calculations of the (100) surface predict the appearance of three Dirac cones in the surface Brillouin zone [2]. We perform angle-resolved photoemission (ARPES) below 1 K and do not observe the predicted Dirac cones at Γ or X. Moreover, the Fermi surface is made up of steeply dispersing bulk Sm5d states. The Sm2+ 4f band and the hybridization gaps where the surface states are expected [2] are too far (∼20 meV) below the Fermi energy in order to contribute to the transport. These results will be discussed in comparison to other ARPES studies.
J. C. Cooley, M. C. Aronson, Z. Fisk, P. C. Canfield, Phys. Rev. Lett. 74, 1629 (1995)
F. Lu, J. Zhao, H. Weng, Z. Fang, Xi Dai, Phys. Rev. Lett. 110, 096401 (2013)

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