Persistent current induced by magnetic impurities

TL;DR

This paper calculates the average persistent current in mesoscopic rings, revealing a significant contribution from magnetic impurities related to electron spin fluctuations, especially at low temperatures.

Contribution

It introduces a new mechanism for persistent current induced by magnetic impurities, surpassing electron-electron interaction effects in magnitude.

Findings

Magnetic impurities contribute significantly to persistent current.

The new current contribution scales as $E_c^2/(kT\,\phi_0)$.

This contribution can be larger than electron-electron interaction induced currents.

Abstract

We calculate the average persistent current in a normal conducting, mesoscopic ring in the diffusive regime. In the presence of magnetic impurities, a contribution to the persistent current is identified, which is related to fluctuations in the electron spin density. Assuming a spin-flip scattering rate which is comparable to the Thouless energy E_c and low temperature, this new contribution to the persistent current is of the order $I\sim E_c^2/(kT\phi_0)$, which is considerably larger than the persistent current induced by the electron-electron interaction.