Molecular beam epitaxial growth: simulation and continuum theory

We present results of atomistic simulations of an ideal MBE growth process in 1+1 dimensions and make connection with continuum models of interface growth. We argue that the KPZ equation is not the relevant continuum equation for MBE growth at intermediate temperatures, where overhangs and bulk defects can be neglected. Instead, a fourth-order linear equation gives the same growth exponents obtained in the numerical simulations but leads to unphysical properties of the long-time surface morphology. We propose a new nonlinear growth equation different from the KBZ equation, as the relevant dynamical equation for ideal MBE growth