Ab initio calculation of surface-resistivity induced by 3d adatoms on simple metals

We report on density-functional calculations of the surface resistivity rho (s) induced by isolated 3d adatoms on metal substrates. In the present work, we concentrate on the case of nonmagnetic adatoms on semi-infinite Al-like jellium, and the effects of magnetism and atomic relaxations are left as a subject for future work. For a fixed adatom-substrate distance z(a), the calculated rho (s) follows a characteristic bell-shaped curve as a function of the 3d valence as in the case of bulk impurities. For all the elements up to Fe, rho (s) is found to become even larger than the residual resistivity for the corresponding impurities in bulk jellium when the adatoms are located by similar to1 bohr outside jellium. Also, for these elements, the calculated rho (s) as a function of z(a) attains a maximum before decaying exponentially at larger z(a). Detailed analyses of the induced density of states: (DOS) indicate that such a maximum is explained in terms of the behavior of the p component of the adatom-induced DOS at the Fermi level, which is found to be significantly enhanced due to charge redistributions when the atom is very close to the surface.