Abstract
We discuss size-dependent elastic properties in the context of our recent work on the mechanics of silicon nanowires. The results are based on first-principles density functional theory calculations. We focus especially on the size dependence of the Young's modulus, but also comment on the size dependence of the residual stress and the equilibrium length of the hydrogen-passivated Si nanowires. We compare these results to prior results from classical molecular dynamics based on empirical potentials.