Surface roughness and surface-induced resistivity of gold films on mica: influence of roughness modelling

We report measurements of the temperature dependent resistivity rho(T) of a gold film 70 nm thick deposited on mica preheated to 300 degrees C in UHV performed between 4 K and 300 K, and measurements of the surface topography of the same film performed with a scanning tunnelling microscope (STM). Fr om the roughness measured with the STM we determine the parameters delta (r .m.s. amplitude) and xi (lateral correlation length) corresponding to a Gau ssian and to an exponential representation of the average autocorrelation f unction (ACF). We use the parameters delta and xi determined via STM measur ements to calculate the quantum reflectivity R, and the temperature depende nce of both the hulk resistivity po(T) and of the increase in resistivity D elta rho(T) = rho(T) - rho(0)(T) induced by electron-surface scattering on this film, according to a modified version of the theory of Sheng, Xing and Wang recently proposed (Munoz et al 1999 J. Phys.: Condens. Matter 11 L299 ). The resistivity rho(0) in the absence of surface scattering predicted fo r a Gaussian representation of the ACF is systematically smaller than that predicted for an exponential representation of the ACF at all temperatures. The increase in resistivity Delta rho induced by electron-surface scatteri ng predicted for a Gaussian representation of the average ACF data is about 25% larger than the increase in resistivity predicted for an exponential r epresentation of the ACF data.