Anomalous scaling of the surface roughness during Cu electrodeposition

For Cu electrodeposition from additive-free acid sulphate electrolyte, the local roughness does not always remain constant as required by the standard Family-Vicsek scaling ansatz. Instead, an additional scaling exponent is required to characterize the time evolution of the local roughness. The surface width w(l,t) scales as t(betaloc) l(H) when the deposition time t is large or the size I of the region over which w is measured is small, and as t(beta+betaloc) when l is large, or t small. When electrochemical parameters are varied, only beta(loc) changes, while the other power law exponents H and beta remain constant.