CROSSOVER BEHAVIORS IN A MOLECULAR-BEAM EPITAXIAL-GROWTH MODEL

We study a growth model for ideal molecular-beam epitaxial growth, in which landed atoms relax to local energy minima. In the calculation of the binding energy, we consider the next-nearest-neighbor interaction as well as the nearest-neighbor interaction. It is considered that this model, a natural extension of the Wolf-Villain model, is described by the most general continuum equation up to fourth order for a conservative growth. Numerical simulations on one-dimensional substrates show crossover behaviors of the growth exponents β and α; β=1/3 and α=1 change to β=1/4 and α=1/2 (Edwards-Wilkinson class) via β=3/10 and α=3/4. These rexsults are supported by the calculations of the correlation function and the surface diffusion currents on tilted substrates. We also give an intuitive argument for these results. © 1995 The American Physical Society.