Finite-Temperature Quasicontinuum: Molecular Dynamics without All the Atoms

Using a combination of statistical mechanics and finite-element interpolation, we develop a coarse-grained (CG) alternative to molecular dynamics (MD) for crystalline solids at constant temperature. The new approach is significantly more efficient than MD and generalizes earlier work on the quasicontinuum method. The method is validated by recovering equilibrium properties of single crystal Ni as a function of temperature. CG dynamical simulations of nano-indentation reveal a strong dependence on temperature of the critical stress to nucleate dislocations under the indenter.