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

Abstract

We study the nonequilibrium dynamics of voltage-induced insulator-to-metal transition in the double-exchange model. By incorporating nonequilibrium Green's function method into large-scale Landau-Lifshitz-Gilbert dynamics simulation, we show that the transition to the low-resistance state is initiated by the nucleation of a thin ferromagnetic conducting layer at the anode. The resultant metal-insulator interface is then driven toward the opposite electrode by the voltage stress, giving rise to a growing metallic region. Once the transformation is completed, the system remains a metastable ferromagnetic metal after the voltage bias is removed. This resistance transition is analogous to the electroforming process in resistive switching phenomena. We further show that the initial transformation kinetics is well described by the Kolmogorov-Avrami-Ishibashi model with an effective dimension dependent on the applied voltage. Implications of our results for resistive switching in lanthanum manganites are also discussed.

Machine learning nonequilibrium electron forces for adiabatic spin dynamics

“…where the lesser self-energy Σ < is related to the Σ r through the dissipation-fluctuation theorem. The electronic force on the spins, which is obtained from the generalized Hellmann-Feynman theorem, can then be computed from the lesser Green's function [64][65][66][67][68][69]]…”

“…The spatio-temporal dynamics of this insulator-tometal phase transformation has recently been systematically studied based on the NEGF-LLG simulations [69]. The kinetics of the nonequilibrium phase transition described above is essentially governed by the propagation of the FM-AFM domain walls.…”