Diffusion in disordered fractals

¹ Institut für Physik, Technische Universität Chemnitz - D-09107 Chemnitz, Germany
² Condensed Matter Physics Research Centre, Jadavpur University Kolkata 700032, India

Received: 5 October 2004
Accepted: 11 February 2005

Abstract

Diffusion in disordered media can be modelled by the anomalous diffusion in fractals. Up to now, usually regular fractals were used as models for such disordered systems. Here we study disordered fractals in an attempt to capture the random nature of the disordered material. In particular, we investigate the diffusion in fractals obtained by randomly mixing different Sierpinski carpet generators. We find that the random-walk exponent d_w shows strong dependance on the mixture composition. For the mixed system it can be higher or lower than both the pure components. Further, d_w may decrease on mixing, indicating faster diffusion in the disordered system.