Spin–orbit splitting in ultra thin Ag films on Cu(1 0 0)

Ultra thin silver films deposited on Cu(1 0 0) have been studied by high energy and angle resolved photoemission spectroscopy (ARPES), scanning tunnelling microscopy (STM) and low electron energy diffraction (LEED). An effective spin–orbit splitting in the Ag 4d was measured as the morphology of deposited silver was changing from the silver–copper alloy to separated silver–copper systems. It is found that in the limit of small silver concentration the spin–orbit splitting is equal to the atomic value, i.e., 0.22 eV. With the increasing silver concentration the splitting continuously increases reaching the value of 0.28 eV at the saturation coverage (0.9 ML). Possible effects that induce increase of the effective spin–orbit splitting are discussed.