Terrace width distributions for vicinal surfaces with steps of alternating stiffness

For the typical elastic interactions between steps, the generalized Wigner distribution (GWD) has been shown to be in excellent quantitative agreement with terrace width distributions (TWDs) calculated from numerical simulations. Here we show that the TWDs of vicinal surfaces with steps of alternating stiffness (but the same sort of step-step repulsions) are also given by the GWD. In the key parameter, the dimensionless repulsion strength, the step stiffness is generalized to twice the “reduced stiffness” of the two kinds of steps, as befits the inertial nature of stiffness. These results should also be applicable to more general surfaces with steps of different stiffness.