First-principles determination of dislocation properties in magnesium based on the improved Peierls–Nabarro equation

We have employed the improved Peierls–Nabarro equation to study the dislocation properties on the basal plane in Mg. The generalized-stacking-fault (GSF) energy surface entering the equation is calculated by using first-principles density functional theory. The core structures including the core widths both of the edge and screw components and dissociation behavior for edge dislocations have been investigated. The distance of two partials in our calculation agrees well with the values obtained from the direct ab initio simulation. Various GSF energies from the previous ab initio calculations have also been used to determine the core properties. We demonstrate that the dissociated distance is not only determined by stable stacking-fault energy but also sensitive to the unstable stacking-fault (USF) energy and the larger the USF energy the smaller the dislocation distance. In addition because of the strong overlap of two partials the structure of dislocations in Mg cannot be dealt with using the one-dimensional model.