Theory of electronic and spin-orbit proximity effects in graphene on Cu(111)

• Published in: Physical review. B 2016-04, Vol.93 (15), Article 155142
• Main Authors: Frank, Tobias, Gmitra, Martin, Fabian, Jaroslav
• Format: Article
• Language: English
• Subjects: Condensed matter; Copper; Graphene; Mathematical models; Orbitals; Proximity; Proximity effect (electricity); Spin-orbit interactions
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.93.155142

We study orbital and spin-orbit proximity effects in graphene adsorbed to the Cu(111) surface by means of density functional theory (DFT). The proximity effects are caused mainly by the hybridization of graphene [pi] and copper d orbitals. Our electronic structure calculations agree well with the experimentally observed features. We carry out a graphene-Cu(111) distance dependent study to obtain proximity orbital and spin-orbit coupling parameters, by fitting the DFT results to a robust low energy model Hamiltonian. We find a strong distance dependence of the Rashba and intrinsic proximity induced spin-orbit coupling parameters, which are in the meV and hundreds of [mu]eV range, respectively, for experimentally relevant distances. The Dirac spectrum of graphene also exhibits a proximity orbital gap, of about 20 meV. Furthermore, we find a band inversion within the graphene states accompanied by a reordering of spin and pseudospin states, when graphene is pressed towards copper.