Study of the Impact of Ionic Liquid Gating and Uniaxial Strain on the Strongly Correlated Electron Material Samarium Hexaboride (SmB₆)

Samarium Hexaboride (SmB₆) is a strongly correlated electron material well known for its robust insulating bulk and its topologically protected surface states. In this study, we analyze the influence of electrostatic doping through ionic liquid gating and applied pressure via uniaxial strain on the electrical resistance behavior of SmB₆. Magneto-transport studies on SmB₆ are complicated by conductive subsurface cracks, which strongly pollute Hall measurements. To minimize the effects, Hall bar samples were prepared by polishing all four elongated surfaces. Furthermore, data analysis was carried out by converting to Hall conductivity from resistivity due to a lessened effect of subsurface cracks. The small size of the samples meant that the scale of the contacts could not be treated as negligibly small. Thus, to accurately obtain the bulk and surface transport parameters, we performed finite element analysis on our geometries. Ionic liquid was used to modify the charge carrier density on the surface between applied voltages of -2 and 2 V. Within this range the resistance plateau varied as much as 75%. Using a strain cell, we measured a Hall bar under compression and tension, and we found variations in the resistance plateaus that were notably less pronounced compared to previous literature.