Dynamical scaling of sputter-roughened surfaces in 2+1 dimensions.

: The asymptotic scaling behavior of sputter-roughened surfaces is of great current interest. In particular, the disparately wide-ranging values of the growth exponent found experimentally, and whether sputter-roughening belongs to the Kardar-Parisi-Zhang universality class in 2+1 dimensions, are two interesting issues. We address these issues using simulations of an atomistic model. The asymptotic scaling appears to be Edwards-Wilkinson. Crossover behavior in the model leads to effective growth exponents that vary widely depending upon the regime of observation.