Nonequilibrium Dynamics of Gating-Induced Resistance Transition in Charge Density Wave Insulators

TL;DR

This paper investigates the nonequilibrium dynamics of gate-induced insulator-to-metal transitions in charge density wave insulators using large-scale simulations, revealing threshold voltages, nucleation processes, and domain wall dynamics.

Contribution

It introduces a comprehensive numerical approach combining Brownian dynamics and nonequilibrium Green's functions to study the transition mechanisms in CDW systems.

Findings

Threshold bias voltage is set by in-gap edge modes.

Transition involves nucleation of a metallic layer at the electrode.

Metallic domains grow via interface propagation under bias.

Abstract

We present a comprehensive numerical investigation of the gate-induced insulator-to-metal transition in the charge-density-wave (CDW) phase of the Holstein model. Large-scale Brownian dynamics simulations are performed, in which the forces acting on the lattice degrees of freedom are evaluated using the nonequilibrium Green's function formalism. We demonstrate that the onset of CDW instability requires a threshold bias voltage set by the energy of in-gap edge modes. At sufficiently large voltages, the system undergoes an abrupt transition to a metallic state, reminiscent of dielectric breakdown. In the intermediate-voltage regime, our simulations reveal that the transition to a low-resistance state is initiated by the nucleation of a thin conducting layer at the gated electrode. The resulting metal-insulator interface subsequently propagates across the system under the applied bias, leading to the growth of a metallic domain. We further analyze the voltage- and temperature-dependent dynamics of the associated domain walls.