Adsorption, diffusion, and incorporation of Pd in cubic (001) Cu(3)N: A DFT study

We have studied the structural properties of the clean (001) surface of Cu(3)N in the anti-ReO(3) structure (space group Pm(3)m) using Density Functional Theory (DFT). We found that a small relaxation occurs: the first interlayer distance is contracted by ~1.4%, while the second one is expanded by 0.55%. We have also investigated the adsorption of Pd on the (001)-Cu(3)N surface and determined the energy barriers for lateral diffusion in the topmost layer. The incorporation of Pd atoms into the bulk was also considered by calculating adsorption sites and energy barriers. It is found that the most stable configuration corresponds to the Pd atom occupying the center of the cube. To arrive to this site, the atom has to overcome an energy barrier of 0.78 eV. This configuration is more stable than adsorption of the Pd atom on the surface.