Magnetic response of interacting electrons in a spatially non-uniform disordered multi-channel system: Exact and mean-field results

TL;DR

This paper investigates the magnetic response of interacting electrons in a non-uniform disordered multi-channel system, revealing novel phenomena like half flux-quantum periodic currents and contrasting effects of disorder, using exact and mean-field methods.

Contribution

It provides the first detailed analysis of magnetic response in non-uniform disordered systems with Hubbard interactions, highlighting unique disorder effects and flux periodicities.

Findings

Contrasting magnetic responses beyond a critical disorder level.

Observation of half flux-quantum periodic currents.

Disorder effects are significantly different from uniform disordered systems.

Abstract

In this work we explore magnetic response of interacting electrons in a spatially non-uniform disordered system, where impurities are introduced in one sector of the geometry keeping the other one free. The interaction among the electrons are taken in the well known Hubbard form which leads to several anomalous features in energy spectra and flux driven circular current, depending on the concentration of up and down spin electrons. For smaller systems with less number of electrons we present exact results which always give a clear picture to understand the basic mechanisms, while for large systems having higher number of electrons mean-field results are given. The effect of disorder is very interesting. Beyond a critical disorder, completely contrasting signature is obtained compared to uniform disordered systems, and the phenomenon becomes more promising when the Hubbard interaction is included. Along with these features, we find unusual half flux-quantum periodic current at some typical cases and a suitable explanation of it is provided. Our detailed analysis may be utilized to study magnetic response of interacting electrons in other similar kind of non-uniform disordered systems.