Persistent Currents in Small, Imperfect Hubbard Rings

TL;DR

This study investigates how imperfections in small Hubbard rings affect persistent currents, revealing that imperfections can both decrease and increase these currents depending on their nature and electron interactions.

Contribution

It provides new insights into the effects of localized and non-localized imperfections on persistent currents in small Hubbard rings using exact diagonalization.

Findings

Imperfections generally decrease persistent currents

Certain imperfections can increase persistent currents

Electron spin significantly influences the results

Abstract

We have done a study with small, imperfect Hubbard rings with exact diagonalization. The results for few-electron rings show, that the imperfection, whether localized or not, nearly always decrease, but can also \emph{increase} the persistent current, depending on the character of the imperfection and the on-site interaction. The calculations are generally in agreement with more specialized studies. In most cases the electron spin plays an important role.