Ab initio study of a grain boundary in gold

The total energy of a grain boundary in a transition metal is calculated in an ab initio manner. Such calculations are now feasible using a plane-wave basis set provided that an optimally convergent pseudopotential is used. The investigation focuses on resolving two competing atomic models for the Σ=5 [001] twist boundary in gold. It is found that the model of lower energy, which involves small atomic displacements, corresponds to a structure determined both experimentally, using quantitative x-ray-diffraction techniques, and theoretically, using the embedded-atom method.