# 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 SmB**_{6} — •Peter Hlawenka^{1}, Emile Rienks^{1}, Konrad Siemensmeyer^{1}, Eugen Weschke^{1}, Andrei Varykhalov^{1}, Natalya Shitsevalova^{2}, Slavomir Gabani^{3}, Karol Flachbart^{3}, and Oliver Rader^{1} — ^{1}Helmholtz-Zentrum Berlin — ^{2}Institute for Problems of Material Science, Kiev, Ukraine — ^{3}IEP, Slovak Academy of Science, Kosice

The system SmB_{6} 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 Sm4*f*-5*d* 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 Sm5*d* states.
The Sm^{2+} 4*f* 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)