Anomalous temperature dependence of the phase-coherence length for inhomogeneous gold films

Abstract

Magnetoresistance measurements as well as transmission-electron-microscopy investigations are carried out for thin gold films of varied topography. For gold films with percolative structure we find an anomalous temperature dependence of the phase coherence length ${\mathit{L}}_{\mathrm{\ensuremath{\varphi}}}$(T), if the percolation correlation length ${\ensuremath{\xi}}_{\mathit{p}}$>${\mathit{L}}_{\mathrm{\ensuremath{\varphi}}}$(T). This can be understood in terms of anomalous diffusion. Moreover, comparing these results with ${\mathit{L}}_{\mathrm{\ensuremath{\varphi}}}$(T) for nonpercolating (homogeneous) gold films yields critical exponents of two-dimensional percolation, quantitatively.