Non-Kondo-like electronic structure in the correlated rare-earth hexaboride YbB(6)

Madhab Neupane; Su-Yang Xu; Nasser Alidoust; Guang Bian; D J Kim; Chang Liu; I Belopolski; T-R Chang; H-T Jeng; T Durakiewicz; H Lin; A Bansil; Z Fisk; M Z Hasan

doi:10.1103/PhysRevLett.114.016403

Non-Kondo-like electronic structure in the correlated rare-earth hexaboride YbB(6)

Phys Rev Lett. 2015 Jan 9;114(1):016403. doi: 10.1103/PhysRevLett.114.016403. Epub 2015 Jan 7.

Authors

Madhab Neupane¹, Su-Yang Xu¹, Nasser Alidoust¹, Guang Bian¹, D J Kim², Chang Liu¹, I Belopolski¹, T-R Chang³, H-T Jeng⁴, T Durakiewicz⁵, H Lin⁶, A Bansil⁷, Z Fisk², M Z Hasan⁸

Affiliations

¹ Joseph Henry Laboratory and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
² Department of Physics and Astronomy, University of California at Irvine, Irvine, California 92697, USA.
³ Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
⁴ Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan and Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
⁵ Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
⁶ Graphene Research Centre, Department of Physics, National University of Singapore, Singapore 117542, Singapore.
⁷ Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA.
⁸ Joseph Henry Laboratory and Department of Physics, Princeton University, Princeton, New Jersey 08544, USA and Princeton Center for Complex Materials, Princeton University, Princeton, New Jersey 08544, USA.

PMID: 25615485
DOI: 10.1103/PhysRevLett.114.016403

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's points, while the f orbital that would be relevant for the Kondo mechanism is ∼1 eV below the Fermi level. Our first-principles calculation shows that the topological state that 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.