Effects of multilayer relaxation and surface roughness on the electronic properties of Pd/W(110) and Pd/W(001)

By using the full potential linearized augmented plane wave method, the structural and electronic properties of Pd/W(001) and Pd/W(110) are investigated. Through force calculations, the Pd adlayer is found to remove the surface relaxation almost completely for the W(110) substrate but only partially for the W(001) substrate. While the interfacial charge polarization plays a key role for the Pd/W bonding in both systems, the effects of interfacial hybridization is also important for Pd/W(001). Interestingly, the change of work function induced by the Pd adlayer is +1.04 eV for W(001) but is −0.13 eV for W(110) — a result which agrees with experiment.