By using an ultra-soft pseudopotentials method based on the density-functional theory, calculations were made of the generalized stacking fault energies for the [100](110), [00¯1](110), and [1¯11](110) slip systems in body-centered cubic Fe within the local density approximation, spin-polarized local density approximation, generalized gradient approximation, and spin-polarized generalized gradient approximation. spin-polarized local density approximation and spin-polarized generalized gradient approximation give much higher unstable stacking fault energies than local density approximation and generalized gradient approximation. The results showed that generalized stacking fault energy was sensitive to the spin state of the system. A spin-polarized calculation should be considered for the slip systems such as [1¯11](110). From the obtained generalized stacking fault energy curves, the edge dislocation properties of [100](010), [00¯1](110), and ½[1¯11](110) within the framework of the Peierls-Nabarro model were demonstrated. It showed that the spin-polarized calculations gave a narrower dislocation core width, higher unstable stacking fault energy, and larger maximum restoring stress as compared with non-spin-polarized calculations.

Generalized Stacking-Fault Energy and Dislocation Properties in BCC Fe - a First-Principles Study. J.A.Yan, C.Y.Wang, S.Y.Wang: Physical Review B, 2004, 70[17], 174105 (5pp)