Modeling of the gate-controlled Kondo effect at carbon point defects in graphene

Abstract

Carbon point defects in graphene induce local magnetic moments in the unbound \ensuremath{\sigma} orbital as well as in a ferromagnetically coupled bound state in the $\ensuremath{\pi}$ conduction band. The local curvature of the graphene sheet determines the hybridization strength to the originally orthogonal conduction band. Here, the authors investigate a two-orbital model, comprising the two localized orbitals as a function of the gate-controlled chemical potential. They identify three different low-temperature regimes. The corresponding distinct spectral functions agree well with recent scanning tunneling data, obtained on different carbon point defects.