SURFACE GROWTH IN A MODEL OF MOLECULAR-BEAM EPITAXY WITH CORRELATED NOISE

We study the effect of correlated noise on a model of molecular-beam epitaxy (MBE), in which desorption and formation of defects can be neglected. The MBE growth model is described by a random deposition process in which the deposited particles can relax to kink sites maximizing the number of saturated bonds. With only Gaussian white noise, the growth exponent beta, defining the interface width W approximately t-beta at intermediate time t, is known to be beta = 3/8. We have solved exactly a continuum model and have determined the surface growth exponents alpha and beta, in the presence of spatially and temporally correlated noise of the form <eta(x,t)eta(x',t)> approximately \x-x'\2-rho-d' \t-t'\2-theta-1, where d' is the interface dimension and rho and theta are the noise correlation parameters. Direct simulation of this noise spectrum in a (1 + 1)-dimensional model confirms our theoretical predictions. Agreement between theory and simulation in this more general case of correlated noise lends further support to the correspondence between the continuum model on which the theory is based and the discrete lattice models that are closer to experimental situations.