Systematic manipulation of the surface conductivity of SmB_{6}

Abstract

We show that the resistivity plateau of SmB_{6} at low temperature, typically taken as a hallmark of its conducting surface state, can systematically be influenced by different surface treatments. We investigate the effect of inflicting an increasing number of handmade scratches and microscopically defined focused ion beam-cut trenches on the surfaces of flux-grown Sm_{1−x}Gd_{x}B_{6} with x=0 and 0.0002. Both treatments increase the resistance of the low-temperature plateau, whereas the bulk resistance at higher temperatures largely remains unaffected. Notably, the temperature at which the resistance deviates from the thermally activated behavior decreases with cumulative surface damage. These features are more pronounced for the focused ion beam treated samples, with the difference likely being related to the absence of microscopic defects such as subsurface cracks. Therefore, our method presents a systematic way of controlling the surface conductance.