Magnetic field induced insulator-to-metal Mott transition in λ-type organic conductors

The effects of a magnetic field on the Mott transition, a longstanding issue in condensed matter physics, are studied using magnetoresistance measurements for organic Mott insulators, $\ensuremath{\lambda}\text{\ensuremath{-}}{(\text{BETS})}_{2}{\mathrm{GaBr}}_{x}{\mathrm{Cl}}_{4\ensuremath{-}x}$, up to 55 T. We demonstrate that an insulator-to-metal transition with a first-order nature and a successive superconductor-to-insulator-to-metal transition are induced by magnetic fields. We discuss the difference in magnetic susceptibility between the insulating and metallic phases, which is a key factor in inducing these transitions. Field induced transitions in experimentally feasible fields under ambient pressure conditions lead to further experimental verification of Mott transitions.