Diffusion and electromigration on disordered surfaces
Fachbereich Physik, Universität GH Essen, 45117 Essen, Germany
Published online: 15 July 2000
We study a one-dimensional disordered solid-on-solid model in which neighboring columns are shifted by quenched random phases. The static height-difference correlation function displays a minimum at a nonzero temperature. The model is equipped with volume-conserving surface diffusion dynamics, including a possible bias due to an electromigration force. In the case of Arrhenius jump rates a continuum equation for the evolution of macroscopic profiles is derived and confirmed by direct simulation. Dynamic surface fluctuations are investigated using simulations and phenomenological Langevin equations. In these equations the quenched disorder appears in the form of time-independent random forces. The disorder does not qualitatively change the roughening dynamics of near-equilibrium surfaces, but in the case of biased surface diffusion with Metropolis rates it induces a new roughening mechanism, which leads to an increase of the surface width as W∼t1/4.
PACS: 68.35.Fx – Diffusion; interface formation / 05.70.Ln – Nonequilibrium and irreversible thermodynamics / 61.43.Dq – Amorphous semiconductors, metals, and alloys
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000