Surface Relaxation Mechanisms in the Morphological Equilibration of Crystal Surfaces

Abstract

The phenomenology of surface relaxation below the roughening temperature <i>T_R</i> is shown via kinetic Monte Carlo simulation to exhibit extremely non-classical behavior depending on (1) initial morphology and (2) kinetic rate laws for atom motion. However, within the temperature and size scale of our simulations there are several different mechanisms that operate. The “pinch-off” mechanism is seen to be operative for ripple relaxation employing <i>i</i>-kinetics. For ripple relaxation employing ∆<i>i</i>-kinetics, pinch-off is seen at short times. At long times, these particular surfaces spontaneously island, and then reduction of line tension drives relaxation. Reduction of line tension also drives relaxation of dimpled surfaces.