Energy barrier for homogeneous dislocation nucleation: Comparing atomistic and continuum models

We compare the energy barriers predicted by continuum mechanics models for homogeneous dislocation nucleation in copper with explicit atomistic calculations. We find that a relatively simple continuum model can agree with full atomistic calculations if the dislocation Burgers vector is allowed to increase continuously during nucleation. The analysis identifies the significant effect of the applied shear stress on the generalized stacking fault energy and leads to a more physical definition of the ideal shear strength.