Recently, the resistance saturation at low temperature in Kondo insulator SmB6, a long-standing puzzle in condensed matter physics, was proposed to originate from topological surface state. Here,we systematically studied the magnetoresistance of SmB6 at low temperature up to 55 Tesla. Both temperature- and angular-dependent magnetoresistances show a similar crossover behavior below 5 K. Furthermore, the angular-dependent magnetoresistance on different crystal face confirms a two-dimensional surface state as the origin of magnetoresistances crossover below 5K. Based on two-channels model consisting of both surface and bulk states, the field-dependence of bulk gap with critical magnetic field (Hc) of 196 T is extracted from our temperature-dependent resistance under different magnetic fields. Our results give a consistent picture to understand the low-temperature transport behavior in SmB6, consistent with topological Kondo insulator scenario.
@article{arxiv.1309.2378,
title = {Magnetoresistance evidence on surface state and field-dependent bulk gap in Kondo insulator SmB6},
author = {F. Chen and C. Shang and Z. Jin and D. Zhao and Y. P. Wu and Z. J. Xiang and Z. C. Xia and A. F. Wang and X. G. Luo and T. Wu and X. H. Chen},
journal= {arXiv preprint arXiv:1309.2378},
year = {2015}
}