Behavior of a Magnetic Impurity in Graphene in the Presence of a Vacancy

TL;DR

This study uses quantum Monte Carlo methods to explore how a magnetic impurity behaves near a vacancy in graphene, revealing unique spectral and magnetic properties influenced by vacancy-induced localized states.

Contribution

It demonstrates that the magnetic impurity's properties depend on vacancy-related localized states rather than the impurity orbital energy, a novel insight into impurity-vacancy interactions.

Findings

Adatom properties depend on vacancy-induced localized state energy.

Spectral density and magnetic susceptibility show novel behavior.

Adatom behavior differs significantly with and without vacancy.

Abstract

With quantum Monte Carlo methods, we investigate the consequences of placing a magnetic adatom adjacent to a vacancy in a graphene sheet. We find that instead of the adatom properties depending on the energy of the adatom orbital, as in a single impurity problem, they develop a dependence on the energy of the split localized state associated with the single vacancy problem. Shifting the chemical potential through this experimentally more accessible energy scale reveals novel behavior in the spectral density, magnetic susceptibility, and the correlations of the adatom spin and charge with those of the conduction electrons. In general, the behavior of the adatom in the presence of a vacancy differs significantly from its behavior in the absence of a vacancy.