Spatio-temporal dynamics of voltage-induced resistance transition in the double-exchange model

TL;DR

This paper uses multi-scale simulations to study how voltage induces a transition from insulator to metal in a double exchange model, revealing nucleation and growth of metallic regions driven by voltage stress.

Contribution

It introduces a combined nonequilibrium Green's function and Landau-Lifshitz-Gilbert simulation approach to analyze the spatio-temporal dynamics of voltage-induced phase transitions.

Findings

Nucleation of ferromagnetic conducting layer at the anode initiates the transition.

Metallic regions grow and move toward the opposite electrode under voltage stress.

Transition kinetics follow the Kolmogorov-Avrami-Ishibashi model with voltage-dependent effective dimension.

Abstract

We present multi-scale dynamical simulations of voltage-induced insulator-to-metal transition in the double exchange model, a canonical example of itinerant magnet and correlated electron systems. By combining nonequilibrium Green's function method with large-scale Landau-Lifshitz-Gilbert dynamics, we show that the transition from an antiferromagnetic insulator to the low-resistance state is initiated by the nucleation of a thin ferromagnetic conducting layer at the anode. The metal-insulator interface separating the two phases is then driven toward the opposite electrode by the voltage stress, giving rise to a growing metallic region. We further show that the initial transformation kinetics is well described by the Kolmogorov-Avrami-Ishibashi model with an effective spatial-dimension that depends on the applied voltage. Implications of our findings for the resistive switching in colossal magnetoresistant materials are also discussed.