Ionic liquid gating on Al-flux grown SmB₆ using Hall bar geometry

Samarium hexaboride (SmB₆) is a correlated material in which strong f-d interactions lead to the opening of a small hybridization gap below 100 K at the Fermi energy. Below 4 K, the plateau in resistivity which was a long standing mystery in SmB₆ has been proposed to arise from a crossover to surface conduction due to topological effects. We investigate how this plateau, as well as the corresponding plateau in the Hall coefficient, can be tuned by gating with the ionic liquid DEME-TFSI. Results are obtained on an Al-flux grown sample in Hall bar geometry prepared by finely polishing on all sides. The sample is suspended in the ionic liquid to ensure that all surfaces contributing to transport are gated. We find that resistivity can be changed by over 15% in the range of accessible voltages in the liquid, and that the Hall coefficient demonstrates a much larger effect of up to 33% change over the same range. We also present a model based on measured parameters of the 2D Fermi surface in SmB₆ to explore these changes.