Pattern formation and nonlinear evolution in alloy surfaces by ion-beam sputtering

Nanoscale pattern formation on surfaces by ion beam sputtering is driven by the competition between the erosion and the diffusion processes. In alloys, these processes are component-dependent. We present a kinetic Monte Carlo model for sputtering of alloy surfaces which exhibits morphological ripples and compositional patterns. The evolution of the ripple amplitude shows a crossover from an early stage exponential growth to a later stage power-law growth. We also present a nonlinear dynamic model which shows both the crossover and the surface patterns, confirming the importance of nonlinear terms in understanding the dynamics of alloy sputtering.