Electronic Structure of Heavy Halogen Atoms Adsorbed on the Cu(111) Surface: A Combined ARPES and First Principles Calculations Study

By means of angle-resolved photoemission spectroscopy and density functional theory calculations, we investigate the electronic structure of a Br or I atom overlayer on the Cu(111) surface produced by the well-known Ullmann coupling reaction. We found that the iodine adsorbate induces two spin orbit split highly dispersive bands, which are well-separated from the bulk Cu 3d bands, whereas the bromine-induced bands are flat and largely hybridized with the copper states. Also, our measured constant energy maps show that the I-induced bands have a parabolic shape in the whole surface Brillouin zone, which is confirmed by our calculations. Overall, the agreement between theory and experiments is excellent, giving new insights into the electronic structure of halogen atoms on noble metals and their possible influence on the molecular electronic structure.