Low temperature resistivity studies of SmB6: Observation of two-dimensional variable-range hopping conductivity

We studied electrical resistance of a single-crystalline SmB6 sample with a focus on the region of the “low-temperature resistivity plateau”. Our observations did not show any true saturation of the electrical resistance at temperatures below 3K down to 70mK. According to our findings, temperature dependence of the electrical conduction in a certain temperature interval above 70mK can be decomposed into a temperature-independent term and a temperature-activated term that can be described by variable-range hopping formula for two-dimensional systems, exp[−(T0/T)1/3]. Thus, our results indicate importance of hopping type of electrical transport in the near-surface region of SmB6.