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NM13.04.01 : Samarium Hexaboride—A Trivial Surface Conductor

5:00 PM–7:00 PM Apr 3, 2018

PCC North, 300 Level, Exhibit Hall C-E

Description
Oliver Rader1

1, Helmholtz-Zentrum Berlin, Berlin, , Germany

The historically first mixed-valence compound and first Kondo insulator SmB6 features a low-temperature resistivity which has remained unexplained for over three decades. Recent predictions as the first topological insulator caused by electron correlation have been supported by a large number of angle-resolved photoemission studies. By proper distinction of Sm and B terminated samples we demonstrate that both types of surface states (at G and X) appear massive, most clearly the one at the zone center which develops a Rashba spin spitting for B termination excluding an odd number of Dirac cones and topological insulator behavior. Even more importantly, it is shown that the metallic surface at low temperature is due to a surface shift of the 4f and a reduced f-d hybridization at the surface which keeps the surface state at X metallic. The present work thus shows that the long-standing problem of the anomalous conductivity of SmB6 has a conventional solution. This result is crucially important in the search for correlated topological insulators.

[1] P. Hlawenka, K. Siemensmeyer, E. Weschke, A. Varykhalov, J. Sánchez-Barriga, N. Y. Shitsevalova, A. V. Dukhnenko, V. B. Filipov, S. Gabáni, K. Flachbart, O. Rader, and E. D. L. Rienks, http://arxiv.org/abs/1502.01542 (2015)

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