Localization and absorption of the local field in two-dimensional composite metal-dielectric films at the percolation threshold

We study in this paper the localization of the electric field and the dielectric properties of thin metal-dielectric composites at the percolation threshold. In particular, the effects of the loss in the metallic components are examined. To this end, such systems are modelled as random RL - C networks, and the local field distribution as well as the effective conductivity are determined by using an exact resolution of Kirchhoff equations in addition to a real-space renormalization group method for comparison. We find a delocalization of the eigenmodes which remain weakly localized for vanishing losses. This result seems to be in agreement with the anomalous absorption observed experimentally for such systems.