Transport of Correlated Electrons through Disordered Chains: A Perspective on Entanglement, Conductance, and Disorder Averaging

TL;DR

This paper studies electron transport in disordered Hubbard chains connected to leads, revealing how disorder and interactions influence conductance, entanglement, and the validity of approximation methods under finite bias conditions.

Contribution

It provides a detailed analysis of transport properties in disordered correlated systems, including the finite-size scaling of conductance and the validation of the Coherent Potential Approximation at finite bias.

Findings

Conductance shows a crossover depending on disorder and interaction strength.

Exponential attenuation of conductance is not always observed.

Coherent Potential Approximation conserves particles at finite bias with correlations.

Abstract

We investigate electron transport in disordered Hubbard chains contacted to macroscopic leads, via the non-equilibrium Green's functions technique. We observe a cross-over of currents and conductances at finite bias which depends on the relative strength of disorder and interactions. The finite-size scaling of the conductance is highly dependent on the interaction strength, and exponential attenuation is not always seen. We provide a proof that the Coherent Potential Approximation, a widely used method for treating disorder averages, fulfils particle conservation at finite bias with or without electron correlations. Finally, our results hint that the observed trends in conductance due to interactions and disorder also appear as signatures in the single-site entanglement entropy.