Orbital selective and tunable Kondo effect of magnetic adatoms on graphene: Correlated electronic structure calculations

TL;DR

This study investigates how dynamical electronic correlations influence the Kondo effect of Co adatoms on graphene, revealing orbital-dependent, tunable, and temperature-sensitive Kondo phenomena with potential for electronic control.

Contribution

It introduces a novel combined density functional and dynamical correlation method to analyze orbital-specific Kondo effects on graphene.

Findings

Kondo peaks are strongly temperature-dependent.

The Kondo effect can be tuned by gate voltage.

Kondo peaks are pinned to graphene's Dirac points.

Abstract

We have studied the effect of dynamical correlations on the electronic structure of single Co adatoms on graphene monolayers with a recently developed novel method for nanoscopic materials that combines density functional calculations with a fully dynamical treatment of the strongly interacting 3d-electrons. The coupling of the Co 3d-shell to the graphene substrate and hence the dynamic correlations are strongly dependent on the orbital symmetry and the system parameters (temperature, distance of the adatom from the graphene sheet, gate voltage). When the Kondo effect takes place, we find that the dynamical correlations give rise to strongly temperature-dependent peaks in the Co 3d-spectra near the Fermi level. Moreover, we find that the Kondo effect can be tuned by the application of a gate voltage. It turns out that the position of the Kondo peaks is pinned to the Dirac points of graphene rather than to the chemical potential.