Spin-spin correlations of magnetic impurities in graphene

TL;DR

This paper investigates how magnetic impurities in graphene interact, revealing a strong low-temperature spin susceptibility enhancement that diverges from traditional RKKY predictions, using numerical quantum Monte Carlo methods.

Contribution

It provides the first numerical analysis of two magnetic impurities in graphene showing significant deviations from RKKY theory at low temperatures.

Findings

Inter-impurity spin susceptibility is strongly enhanced at low temperatures.

The susceptibility diverges, contrasting with the RKKY decay.

Results highlight the importance of many-body effects in graphene impurities.

Abstract

We study the interaction between two magnetic adatom impurities in graphene using the Anderson model. The two-impurity Anderson Hamiltonian is solved numerically by using the quantum Monte Carlo technique. We find that the inter-impurity spin susceptibility is strongly enhanced at low temperatures, significantly diverging from the well-known Ruderman-Kittel-Kasuya-Yoshida (RKKY) result which decays as $R^{-3}$.