Electronic transport in disordered interacting systems

TL;DR

This study uses a novel numerical method to analyze how disorder and electron interactions influence electrical conductance in three-dimensional disordered systems, revealing that interactions can either enhance or suppress transport depending on disorder strength.

Contribution

The paper introduces the Hartree-Fock based diagonalization method for large disordered interacting systems and applies it to study transport properties in the quantum Coulomb glass model.

Findings

Interactions enhance conductance in strongly disordered regimes.

Interactions suppress conductance in weakly disordered regimes.

The influence of interactions on transport depends on disorder strength.

Abstract

We numerically investigate the transport properties of disordered interacting electrons in three dimensions in the metallic as well as in the insulating phases. The disordered many-particle problem is modeled by the quantum Coulomb glass which contains a random potential, long-range unscreened Coulomb interactions and quantum hopping between different sites. We have recently developed the Hartree-Fock based diagonalization (HFD) method which amounts to diagonalizing the Hamiltonian in a suitably chosen energetically truncated basis. This method allows us to investigate comparatively large systems. Here we calculate the combined effect of disorder and interactions on the dissipative conductance. We find that the qualitative influence of the interactions on the conductance depends on the relative disorder strength. For strong disorder interactions can significantly enhance the transport while they suppress the conductance for weak disorder.