Structural and electronic effects of adsorbed Bi on the metallic atomic chains in Au/Si(111)5 x 2

Changes in the structural and electronic properties of the quasi-one-dimensional metal-chain Au/Si(111)5 x 2 reconstruction induced by Bi adsorption were investigated using scanning tunneling microscopy observations, angle-resolved photoelectron spectroscopy measurements and density-functional theory calculations. It was found that Bi atoms substitute the Au atoms in the edge rows of the four-atomic-row Au ridge of the Au/Si(111)5 x 2 reconstruction. The Au/Si(111)5 x 2 surface, which is originally highly heterogenous in its electronic properties, becomes still more heterogeneous upon Bi substitutional adsorption. The overall effect of Bi adsorption resides in the increase of the system Fermi energy due to the electron donation from the Bi atoms to the reconstructed surface. This provides a possibility to tune the metallic properties of the system via controlled Bi dosing.