Enhancement of Persistent Currents by the Coulomb Interaction

TL;DR

This study numerically demonstrates that long-range Coulomb interactions significantly enhance persistent currents in three-dimensional mesoscopic rings, emphasizing the importance of interaction range and screening effects.

Contribution

It introduces a numerical analysis of Coulomb interaction effects on persistent currents in 3D rings using Hartree-Fock approximation, highlighting the role of long-range interactions.

Findings

Coulomb interaction enhances persistent currents

Long-range interactions are essential for enhancement

Screening of disorder contributes to increased currents

Abstract

The persistent current in three-dimensional mesoscopic rings is investigated numerically. The model is tight-binding one with random site-energies and interaction between electrons. The Hartree-Fock approximation is adopted for the interaction between electrons, and models with up to $3\times 4\times 40$ sites are investigated. It is shown that the long-range Coulomb interaction enhances the persistent current considerably for rings with finite width. It is also shown that long-rangedness of the interaction is essential for the enhancement. Screening of the random site-energy is attributed to this enhancement.