Non thermal and purely electronic resistive transition in narrow gap Mott insulators

Mott insulator to metal transitions under electric field are currently the subject of numerous fundamental and applied studies. This puzzling effect, which involves non-trivial out-of-equilibrium effects in correlated systems, is indeed at play in the operation of a new class of electronic memories, the Mott memories. However the combined electronic and thermal effects are difficult to disentangle in Mott insulators undergoing such transitions. We report here a comparison between the properties under electric field of a canonical Mott insulator and a model built on a realistic 2D resistor network able to capture both thermal effects and electronic transitions. This comparison made specifically on the family of narrow gap Mott insulators AM4Q8, (A = Ga or Ge; M=V, Nb or Ta, and Q = S or Se) unambiguously establishes that the resistive transition experimentally observed under electric field arises from a purely electronic mechanism.