The magnetic response of disordered metallic rings: the large contribution of the far levels

TL;DR

This paper calculates the magnetic response of disordered metallic rings, revealing that including high-energy levels significantly increases the predicted response and may explain experimental-theoretical discrepancies.

Contribution

It introduces a BCS model approach that accounts for all energy levels, showing a larger magnetic response than previous local interaction models.

Findings

High-energy levels contribute significantly to magnetic response.

The results may resolve the persistent current discrepancy.

The BCS model enhances understanding of disordered metallic rings.

Abstract

We calculate the orbital linear magnetic response of disordered metallic rings to an Aharonov-Bohm flux using the BCS model for attractive electron-electron interaction. The contribution of all levels including those up to a high energy cutoff results in a much larger value than previously obtained using the local interaction model. The possible relevance of our results to the resolution of the discrepancy between the experimental and theoretical values for the ensemble-averaged persistent currents in these systems is discussed.