Magnetic Impurity in Bernal Stacked Bilayer Graphene

TL;DR

This study explores how magnetic impurities behave in Bernal stacked bilayer graphene, revealing location-dependent magnetic properties and spectral features influenced by stacking symmetry and impurity parameters.

Contribution

It provides a non-perturbative numerical analysis of magnetic impurities in bilayer graphene, highlighting the impact of sublattice position and stacking on impurity magnetism.

Findings

Impurity magnetic moment can be tuned via chemical potential.

Impurity properties depend strongly on sublattice location.

Spectral densities and correlations show consistent spatial dependence.

Abstract

We investigate a magnetic impurity in Bernal stacked bilayer graphene by a non-perturbative numerical exact approach. In the two cases we study, impurity is placed on the top of two different sublattices (A and B) in bilayer graphene. We find that similar to the monolayer case, magnet moment of the impurity could still be tuned in a wide range through changing the chemical potential. However, the property of the impurity depends strongly on its location due to the broken symmetry between sublattices A and B caused by the Bernal stacking. This difference becomes more apparent with the increase in the hybridization and decrease in the on-site Coulomb repulsion. Additionally, we calculate the impurity spectral densities and the correlation functions between the impurity and the conduction-band electrons. All the computational results show the same spatial dependence on the location of the impurity.