Ir 111 Surface State with Giant Rashba Splitting Persists under Graphene in Air

We reveal a giant Rashba effect alphaR 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 stat