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arXiv · 1404.6814

Non-Kondo-like Electronic Structure in the Correlated Rare-Earth Hexaboride YbB$_6$

Madhab Neupane·Su-Yang Xu·Nasser Alidoust·Guang Bian·Dae-Jeong Kim·Chang Liu·Ilya Belopolski·Tay-Rong Chang·Horng-Tay Jeng·Tomasz Durakiewicz·Hsin Lin·Arun Bansil·Zachary Fisk·M. Zahid Hasan
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Abstract

We present angle-resolved photoemission studies on the rare-earth hexaboride YbB$_6$, which has recently been predicted to be a topological Kondo insulator. Our data do not agree with the prediction and instead show that YbB$_6$ exhibits a novel topological insulator state in the absence of a Kondo mechanism. We find that the Fermi level electronic structure of YbB$_6$ has three 2D Dirac cone like surface states enclosing the Kramers' points, while the f-orbital which would be relevant for the Kondo mechanism is $\sim1$ eV below the Fermi level. Our first-principles calculation shows that the topological state which we observe in YbB$_6$ is due to an inversion between Yb $d$ and B $p$ bands. These experimental and theoretical results provide a new approach for realizing novel correlated topological insulator states in rare-earth materials.

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Madhab Neupane, Su-Yang Xu, Nasser Alidoust, Guang Bian, Dae-Jeong Kim, Chang Liu, Ilya Belopolski, Tay-Rong Chang, Horng-Tay Jeng, Tomasz Durakiewicz, Hsin Lin, Arun Bansil, Zachary Fisk, M. Zahid Hasan. 2015-01-20. Non-Kondo-like Electronic Structure in the Correlated Rare-Earth Hexaboride YbB$_6$. https://doi.org/10.1103/physrevlett.114.016403

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