Is SmB6 a strong topological kondo insulator

We study surface state of a generic topological Kondo insulator (TKI) system, viz. SmB6, by performing a mean-field theoretic (MFT) calculation within the frame-work of periodic Anderson model (PAM) using slave-boson technique. The surface metallicity together with bulk insulation is found to require strong f-electron localization. A key distinction between surface states in a conventional insulator and a topological insulator is that along a path connecting two time-reversal invariant momentum (TRIM) in the same BZ, the Fermi energy inside the gap will intersect these surface states either an even or odd number of times. For even (odd) number of surface state crossings, the surface states are topologically trivial (non-trivial). The symmetry consideration and the pictorial representation of surface band structure obtained show odd number of crossing leading to the conclusion that, at least within PAM framework, SmB6 is a strong topological insulator.