Diffusion in the Presence of Topological Disorder (original) (raw)

A general framework is presented for the discussion of Brownian motion in crystals with randomly distributed topological defects. In a two-dimensional lattice with disclinations one finds a nonuniversal subdiffusional behavior if screening in the disclination ensemble is taken into account. Without screening, a Sinai-type diffusion is expected. In a three-dimensional random array of parallel screw dislocations, a Brownian particle shows anisotropic normal diffusion. However, the process no longer is Gaussian and displays long-time tails in the fourth-order cumulants.