Varykhalov, A.; Marchenko, D.; Scholz, M.R.; Rienks, E.D.L.; Kim, T.K.; Bihlmayer, G.; Sánchez-Barriga, J.; Rader, O.: Ir(111) Surface State with Giant Rashba Splitting Persists under Graphene in Air. Physical Review Letters 108 (2012), p. 066804/1-5
10.1103/PhysRevLett.108.066804

Abstract:
We reveal a giant Rashba effect (alpha_R~ 1.3 eV Angström) on a surface state of Ir(111) by angle-resolved photoemission and by density functional theory. It is demonstrated that the existence of the surface state, its spin polarization, and the size of its Rashba-type spin-orbit splitting remain unaffected when Ir is covered with graphene. The graphene protection is, in turn, sufficient for the spin-split surface state to survive in ambient atmosphere. We discuss this result along with indications for a topological protection of the surface state.