Diffusion and electromigration on disordered surfaces

We study a one-dimensional disordered solid-on-solid model in which neighbo ring columns are shifted by quenched random phases. The static height-diffe rence correlation function displays a minimum at a nonzero temperature. The model is equipped with volume-conserving surface diffusion dynamics, inclu ding a possible bias due to an electromigration force. In the case of Arrhe nius jump rates a continuum equation for the evolution of macroscopic profi les is derived and confirmed by direct simulation. Dynamic surface fluctuat ions are investigated using simulations and phenomenological Langevin equat ions. In these equations the quenched disorder appears in the form of time- independent random forces. The disorder does not qualitatively change the r oughening dynamics of near-equilibrium surfaces; but in the case of biased surface diffusion with Metropolis rates it induces a new roughening mechani sm, which leads to an increase of the surface width as W similar to t(1/4).