Revisiting Hall coefficient measurements in samarium hexaboride*

Samarium hexaboride is a correlated material in which strong f-d interactions open a small gap at the Fermi energy below ~100 K. In transport, SmB₆ demonstrates activated behavior down to ~4 K, terminated by a conduction mechanism attributed to the emergence of a topological surface state. We present a study of transport, especially Hall coefficient, from three perspectives. First, we discuss a method of analyzing Hall data at low temperatures, allowing for accurate extraction of mobility from the conductive surface. Next, we re-examine a well-known high-temperature feature in Hall data: the sign change from negative to positive as temperature is raised above ~65 K. This sign change has been attributed to skew scattering due to the strong f-d interactions, but it leads to an inaccurate determination of carrier density and mobility. We discuss a method to improve the accuracy of transport analysis that relies on ARPES data at high temperature to correct for the positive Hall sign. Finally, we present a method of carving a micron-sized Hall bar from SmB₆ to investigate the effect of sample size on transport parameters. Taken together, these results aim to provide a summary of current transport perspectives on SmB₆.