Experimental andab initiostudy of the structural and electronic properties of subnanometer thick Ag films on Pd(111)

Abstract

We present a combined, experimental, and computational investigation of the growth mode and the valence-band structure of $\mathrm{Ag}∕\mathrm{Pd}(111)$, with the focus on the Ag $4d$ derived quantum well states. Low-energy electron diffraction and scanning-tunneling microscopy are used to determine epitaxial, layer-by-layer growth of silver on the palladium substrate. High-resolution (in both energy and angle) photoelectron spectra and ab initio density-functional band-structure calculations are compared for 1 and 2 ML silver films along the $\overline{\ensuremath{\Gamma}}\ensuremath{-}{\overline{M}}^{\ensuremath{'}}$ high symmetry line of the surface Brillouin zone. The observed $d$-derived electronic states and their dispersion are explained in terms of quantum well states. The interaction of the silver $4d$ electronic states with the palladium substrate is discussed.