2012/11/30 by Xiaohang Zhang, N. P. Butch, P. Syers +4 · 1 citation
Materials Science · Physics and Astronomy · #Metallurgical and Alloy Processes #Rare-earth and actinide compounds #Superconductivity in MgB2 and Alloys #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevx.3.011011
published as Phys. Rev. X 3, 011011 (2013) · Accepted for publication in Physical Review X
arxiv created 2013/01/29 · openalex publication_date 2013/02/14 · arxiv updated 2013/02/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
As an exemplary Kondo insulator, SmB6 has been studied for several decades; however, direct evidence for the development of the Kondo coherent state and the evolution of the electronic structure in the material has not been obtained due to the rather complicated electronic and thermal transport behavior. Recently, these open questions attracted increasing attention as the emergence of a time-reversal invariant topological surface state in the Kondo insulator has been suggested. Here, we use point-contact spectroscopy to reveal the temperature dependence of the electronic states in SmB6. We demonstrate that SmB6 is a model Kondo insulator: below 100 K, the conductance spectra reflect the Kondo hybridization of Sm ions, but below ~ 30 K, signatures of inter-ion correlation effects clearly emerge. Moreover, we find evidence that the low-temperature insulating state of this exemplary Kondo lattice compound harbors conduction states on the surface, in support of predictions of nontrivial topology in Kondo insulators.