Overcoming Kondo insulating behavior via disorder, a possible connection of the SmB6 puzzle

Experimental reports of certain low-temperature metallic features for the proposed topological Kondo insulator SmB6 has recently led to serious controversy in the field. Here we address this issue by exploring the effects of disorder in a generic Kondo insulator, by examining an appropriate Anderson lattice model within dynamical mean-field theory. We find that even a moderate strength of disorder produces a very broad distribution of local Kondo scales, which proves sufficient to overcome the typical Kondo insulating behavior, and giving rise to a poor conductor with anomalous properties. Physically, the local regions with very low Kondo temperatures correspond to a locally reduced Kondo gap, thus producing significant disorder-induced in-gap states. Our results offer a possible resolution of the current debate on SmB6.