TRANSPORT PHENOMENA AT ROUGH BOUNDARIES

We present a simple method describing transport processes near rough boundaries. By a proper coordinate transformation we reduce a transport problem with rough walls to an equivalent problem with smooth flat walls, but with some random bulk inhomogeneities. In many cases the last problem can be treated perturbatively, leading to simple expressions for relevant transport coefficients via the correlation function of surface inhomogeneities. We calculate diffusion and conductivity in films, phonon, and photon diffusion, quantum corrections to conductivity, and the single-particle diffusion coefficient.