Topological insulators give rise to exquisite electronic properties due to their spin-momentum locked Dirac-cone-like band structure. Recently, it has been suggested that the required opposite parities between valence and conduction band along with strong spin-orbit coupling can be realized in correlated materials. Particularly, SmB6 has been proposed as candidate material for a topological Kondo insulator. By utilizing scanning tunneling microscopy and spectroscopy measurements down to 0.35 K, we observed several states within the hybridization gap of about ±20 meV on well characterized (001) surfaces of SmB6. The spectroscopic response to impurities and magnetic fields allows to distinguish between dominating bulk and surface contributions to these states. The surface contributions develop particularly strongly below about 7 K which can be understood in terms of a breakdown of the Kondo effect at the surface. Our high-resolution data provide detailed insight into the electronic structure of SmB6, which will reconcile many current discrepancies on this compound.
@article{arxiv.1701.02949,
title = {Additional energy scale in SmB$_6$ at low temperature},
author = {Lin Jiao and Sahana Rößler and D. J. Kim and L. H. Tjeng and Z. Fisk and F. Steglich and S. Wirth},
journal= {arXiv preprint arXiv:1701.02949},
year = {2017}
}