The core structure of dislocations. Peierls model vs. atomic simulations in Pd

When the Peierls model for dislocations is properly generalised to 2D, it is possible to obtain a realistic description of dislocation cores with planar extension. This is an attractive alternative to large-scale atomic simulations. Instead of balancing the acting forces by numerically solving the Peierls integral equation, it is of advantage to use a variational procedure for the energy. The atomic misfit energy can be obtained from the γ-surface as determined by ab initio electron density functional methods. Such even a better description may be obtained than by simulations, which must use empirical interatomic potentials. In Pd where calculations of the γ-surface and atomic simulations are available, the core structure has been determined with the generalised Peierls model and the agreement with the atomic simulations is excellent. Problems connected with determining the Peierls energy will be discussed.