First predicted in 2010 by M. Dzero, V. Galitski and colleagues, the Topological Kondo Insulator (TKI) is a fascinating realization of the 3D topological insulator state in a strongly correlated "Kondo" insulator. Samarium Hexaboride, the archetype Kondo insulator, is an ideal candidate for realizing this exotic state of matter, with hybridization between itinerant conduction electrons and localized f-electrons driving an insulating gap and metallic surface states at low temperatures. SmB6 has been under scrutiny for over 45 years due to peculiar low temperature properties, which have only recently been suggested to arise due to the presence of topologically protected metallic surface states. In an new study led by Dr. Yasuyuki Nakajima in the Center for Nanophysics and Advanced Materials, the topological nature of metallic surface states in SmB6 was investigated by exploiting the existance of a novel surface-born ferromagnetic state and studying its effect on ultra-low temperature magnetotransport properties. Nakajima and co-workers report evidence of one-dimensional surface transport with a quantized conductance value of e2/h originating from the chiral edge channels of ferromagnetic domain walls, providing the strongest evidence to date that topologically non-trivial surface states exist in SmB6.
Read the recently published Letter entitled "One-dimensional edge state transport in a topological Kondo insulator" in Nature Physics (Nov 2015).