Closing the hybridization charge gap in the Kondo semiconductor SmB6 with an ultrahigh magnetic field

Abstract

We have investigated the high-frequency magnetoresistance of Kondo semiconductor ${\mathrm{SmB}}_{6}$ under ultrahigh magnetic fields generated by the electromagnetic flux-compression technique. The semiconductor-metal transition due to closing of the hybridization charge gap was observed at approximately 180 T. The critical magnetic field observed is substantially higher than that reported previously. At temperatures below around 10 K, another transition was observed at a lower field (approximately 80 T). We suggest that the observed 80-T transition relates with the energy scale of quasiparticles such as the spin polaron in the in-gap state.