under pressure*

Electronic transport in the Kondo insulator SmB₆ is dominated at low temperatures by a surface state, which could arise as a consequence of a non-trivial topology of its bulk electronic structure. At ambient pressure, our thermopower measurements have suggested the surface states of SmB₆ to have a strongly enhanced effective mass, consistent with recent quasiparticle interference studies from STM. Pressure increases the hybridization between f- and conduction electrons eventually leading to a metallic state. Here we report thermopower measurements under pressure that illustrate that the Fermi energy of the surface state is unchanged as a function of pressure in the insulating regime. We discuss our results in consideration of Hall effect data that reveal a carrier density increase with increasing pressure.