Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 55: Transport: Topological insulators I (organized by TT)

HL 55.4: 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.
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F. Lu, J. Zhao, H. Weng, Z. Fang, Xi Dai, Phys. Rev. Lett. 110, 096401 (2013)

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