Conductive dislocation lines in SmB6 observed through microwave impedance microscopy*

SmB6 is a candidate for an important class of topological insulator arising from strong correlations. Transport studies suggest surface-dominated transport at low temperatures [1]. Photoemission also revealed 2D in-gap states [2], however the topological nature of these states are under debate [3]. Here we use scanning microwave impedance microscopy to reveal conductive dislocation lines that terminate at step edges of the SmB6 surface. Temperature dependence show that these states persist up to high temperatures beyond any Kondo energy scale. These observations reveal an important conduction channel that must be taken into account for transport studies. Further studies are desired to probe the topological nature of these 1D dislocation states.

[1] Wolgast, S. et al. Low-temperature surface conduction in the Kondo insulator SmB₆. Phys. Rev. B 88, 180405(R) (2013).
[2] Jiang, J. et al. Observation of possible topological in-gap surface states in the Kondo insulator SmB₆ by photoemission. Nat. Commun. 4, 3010 (2013).
[3] Hlawenka, P. et al. Samarium hexaboride is a trivial surface conductor. Nat.Commun. 9, 517 (2018).