Interacting fermions in 1D disordered lattices: Exploring localization and transport properties with lattice density-functional theories

TL;DR

This paper studies how disorder and interactions affect localization and transport in 1D fermionic chains using advanced lattice density-functional theories, revealing dynamical delocalization and increased current.

Contribution

It introduces a modified recursive Lanczos method for efficient quantum transport simulation and adapts the inverse participation ratio for disordered interacting systems within DFT.

Findings

Finite bias enhances delocalization.

Interactions increase steady-state current.

DFT captures complex disorder-interaction effects.

Abstract

We investigate the static and dynamical behavior of 1D interacting fermions in disordered Hubbard chains, contacted to semi-infinite leads. The chains are described via the repulsive Anderson-Hubbard Hamiltonian, using static and time-dependent lattice density-functional theory. The dynamical behavior of our quantum transport system is performed via an integration scheme available in the literature, which we modify via the recursive Lanczos method, to increase its efficiency. To quantify the degree of localization due to disorder and interactions, we adapt the definition of the inverse participation ratio to obtain an indicator which is both suitable for quantum transport geometries and which can be obtained within density-functional theory. Lattice density functional theories are reviewed and, for contacted chains, we analyze the merits and limits of the coherent-potential approximation in describing the spectral properties, with interactions included via lattice density functional theory. Our approach appears to able to capture complex features due to the competition between disorder and interactions. Specifically, we find a dynamical enhancement of delocalization in presence of a finite bias, and an increase of the steady-state current induced by inter-particle interactions. This behavior is corroborated by results for the time-dependent densities and for the inverse participation ratio. Using short isolated chains with interaction and disorder, a brief comparative analysis between time-dependent density-functional theory and exact results is then given, followed by general conclusive remarks.