Direct two-dimensional calculations of grain boundary stiffness

Lennard-Jones based molecular dynamics simulations of capillarity fluctuations in flat, 2D symmetric tilt grain boundaries show that fluctuation in the high symmetry θgb = 38.2° − Σ7 boundary is consistent with capillarity wave theory, with a grain boundary stiffness Γgb = 0.31 ± 0.015ϵ/r0. Low symmetry θgb = 30° − Σ∞ boundary exhibits peaks at certain modes, indicative of vicinal cusps in the Wulff plot.