▎ 摘　　要

Graphene grown catalytically on Ir(111) shows a large substrate-induced spin-orbit splitting of Delta(so) similar to 50 meV in spin- and angle-resolved photoemission. Its origin is hybridization as revealed by large gaps in the pi band. Reducing the growth temperature results in a very large splitting of the Dirac cone, which is found to be of geometric origin and allows for the structural identification of a rotated graphene phase. The spin-orbit splitting on this phase is considerably smaller, which implies that the magnitude of the extrinsic spin-orbit splitting in supported graphene can be controlled by its rotational displacement to the substrate. DOI: 10.1103/PhysRevB.87.115426