Lateral Quantum Well States on Pb Films Grown on Cu Step Surface

The highly ordered Pb films were found to grow on Cu step surface as a ``magic'' heteroepitaxial grown model. The lateral quantum well states in these Pb have been investigated by angle-resolved photoemission. Across the step direction, the quantum well state display a dispersive character, with periodicity in reciprocal space defined by the step superlattice geometry. These observations are compared and analyzed with \textit{ab initio} calculations based on the full-potential linearized augmented plane wave method.