Nonequilibrium Mean-Field Theory of Resistive Phase Transitions

TL;DR

This paper develops a nonequilibrium mean-field theory to understand resistive phase transitions in driven solids, unifying different transition mechanisms and predicting non-analytic current-voltage behavior.

Contribution

It introduces an analytic framework that unifies Landau-Zener and Joule heating mechanisms via an effective thermal description, and proposes a Ginzburg-Landau theory for spatial fluctuations.

Findings

Distinct electronic mechanisms for IMT and MIT identified

Effective temperature explains hot-electron behavior at transition

Predictions of non-analytic I-V behavior near transition

Abstract

We investigate the quantum mechanical origin of resistive phase transitions in solids driven by a constant electric field in the vicinity of a metal-insulator transition. We perform a nonequilibrium mean-field analysis of a driven-dissipative anti-ferromagnet, which we solve analytically for the most part. We find that the insulator-to-metal transition (IMT) and the metal-to-insulator transition (MIT) proceed by two distinct electronic mechanisms: Landau-Zener processes, and the destabilization of metallic state by Joule heating, respectively. However, we show that both regimes can be unified in a common effective thermal description, where the effective temperature $T_{\rm eff}$ depends on the state of the system. This explains recent experimental measurements in which the hot-electron temperature at the IMT was found to match the equilibrium transition temperature. Our analytic approach enables us to formulate testable predictions on the non-analytic behavior of $I$-$V$ relation near the insulator-to-metal transition. Building on these successes, we propose an effective Ginzburg-Landau theory which paves the way to incorporating spatial fluctuations, and to bringing the theory closer to a realistic description of the resistive switchings in correlated materials.