The electronic structures of various types of dislocation in B2 intermetallics (NiAl) and body-centered cubic transition metals were investigated by using the first-principles real space tight-binding linear muffin-tin orbital recursion method. An unusual localization of electronic states within the valence band was observed in the cores of <100>{010} and <100>{011} edge dislocations, but not in <111>{011} edge dislocations. It was shown that the conditions of electron localization were, firstly, a decrease in the number of nearest neighbors (broken bonds) around the central atom of the dislocation core and, secondly, a certain local symmetry of the atomic arrangement in the region of the dislocation core. Thirdly, there was a contribution of d-states to the formation of these interatomic bonds. These conclusions were illustrated by demonstrating that electron localization also occurred in <100>{010} edge dislocations in W, Fe and Ni. In contrast to semiconductors, electron localization in metals took place on bonding orbitals and therefore had a significant impact upon dislocation energetics and chemical bonding. It was suggested that localized electronic states could make a significant contribution to impurity-dislocation interactions in NiAl, and other B2 intermetallics such as CoTi, CoHf and CoZr.

Electron Localization on Dislocations in Metals - Real-Space First-Principles Calculations. O.Y.Kontsevoi, Y.N.Gornostyrev, O.N.Mryasov, A.J.Freeman, M.I.Katsnelson, A.V.Trefilov: Physical Review B, 2001, 64[13], 134103 (12pp)