Aharonov-Bohm effect as a probe of interaction between magnetic impurities

TL;DR

This paper investigates how the Aharonov-Bohm effect can be used to probe the distribution of exchange interactions between magnetic impurities, revealing insights into electron dephasing caused by RKKY interactions in mesoscopic metal rings.

Contribution

It introduces a method to use Aharonov-Bohm conductance oscillations as a probe for the exchange interaction distribution among magnetic impurities.

Findings

Dephasing rate scales as 1/B^2 in strong magnetic fields.

Aharonov-Bohm oscillations reflect the distribution of exchange interactions.

Strong magnetic fields suppress electron coherence via impurity pairs.

Abstract

We study the effects of the RKKY interaction between magnetic impurities on the mesoscopic conductance fluctuations of a metal ring with dilute magnetic impurities. At sufficiently low temperatures and strong magnetic fields, the loss of electron coherence occurs mainly due to the scattering off rare pairs of strongly coupled magnetic impurities. We establish a relation between the dephasing rate and the distribution function of the exchange interaction within such pairs. In the case of the RKKY exchange interaction, this rate exhibits 1/B^2 behavior in strong magnetic fields. We demonstrate that the Aharonov-Bohm conductance oscillations may be used as a probe of the distribution function of the exchange interaction between magnetic impurities in metals.