First-Principles Calculations of the Atomic and Electronic Structures in Au-Pd Slab Interfaces

We performed first-principles calculations using the projector augmented-wave (PAW) method for Au/Pd slab interface models. The calculations of relaxed configurations and energies for the thin Pd layers (3 layers) stacking on Au (111) and Au (100) slabs with an epitaxial relationship represent that Pd overlayers have a lateral expansion in both cases. This trend is in good agreement with experimental results for Pd/Au slabs and Au-Pd core-shell nanoparticles, obtained by electron microscopy, X-ray diffraction, and positron annihilation. In addition, an intermixing configuration near the Au-Pd interface was shown to be more stable than the binary separated one.