Diamagnetic response of Aharonov-Bohm rings: Impurity backward scatterings

TL;DR

This paper presents a theoretical study on how impurity-induced backward scatterings in disordered normal-metal rings lead to a transition from paramagnetic to diamagnetic persistent currents near zero magnetic field.

Contribution

It introduces a detailed analysis of the impurity effects on persistent currents, highlighting the transition from paramagnetic to diamagnetic responses with increasing disorder.

Findings

Diamagnetic responses are caused by multiple impurity backward scatterings.

A transition from paramagnetic to diamagnetic response occurs as disorder increases.

Both analytic calculations and numerical diagonalization confirm the transition.

Abstract

We report a theoretical calculation on the persistent currents of disordered normal-metal rings. It is shown that the diamagnetic responses of the rings in the vicinity of the zero magnetic field are attributed to multiple backward scatterings off the impurities. We observe the transition from the paramagnetic response to the diamagnetic one as the strength of disorder grows using both the analytic calculation and the numerical exact diagonalization.