Dielectric Breakdown of a Mott Insulator

TL;DR

This paper investigates the nonequilibrium steady state and dielectric breakdown of a Mott insulator under a constant electric field, revealing dissipation-controlled current and a breakdown at the Mott gap, challenging traditional models.

Contribution

It provides new insights into the steady-state behavior and breakdown mechanism of Mott insulators under electric fields, beyond the conventional Zener picture.

Findings

Current at weak fields is controlled by dissipation.

Dielectric breakdown occurs when the field matches the Mott gap.

Resonance and quasiparticle meltdown happen at half the Mott gap.

Abstract

We study the nonequilibrium steady state of a Mott insulator coupled to a thermostat and driven by a constant electric field, starting from weak fields, until the dielectric breakdown, and beyond. We find that the conventional Zener picture does not describe the steady-state physics. In particular, the current at weak field is found to be controlled by the dissipation. Moreover, in connection with the electric-field-driven dimensional crossover, we find that the dielectric breakdown occurs when the field strength is on the order of the Mott gap of the corresponding lower-dimensional system. We also report a resonance and the meltdown of the quasiparticle peak when the field strength is half of this Mott gap.