Non-linear conductivity of metals from real-time quantum simulations

TL;DR

This paper introduces a real-time quantum simulation method to model non-linear electrical conductivity in metals, revealing phenomena like negative differential conductivity in liquid aluminum at high current densities.

Contribution

It presents a first-principles approach to simulate non-linear conductivity effects in metals under strong currents, a novel capability in quantum simulations.

Findings

Liquid aluminum exhibits negative differential conductivity at high current densities.

Non-linear conductivity results from a balance between charge accumulation and scattering cross-section changes.

The method enables modeling of non-linear electrical responses from fundamental quantum principles.

Abstract

We simulate bulk materials under strong currents by following in real-time the dynamics of the electrons under an electric field. By changing the intensity of the electric field, our method can model, for the first time, non-linear effects in the conductivity from first principles. To illustrate our approach, we show calculations that predict that liquid aluminum exhibits negative-differential conductivity for current densities of the order of $10^{12}-10^{13}~\mathrm{A/cm^2}$. We find that the change in the non-linear conductivity emerges from a competition between the accumulation of charge around the nuclei that increases the scattering of the conduction electrons, and a decreasing scattering cross-section at high currents.