Calculation of core structure and core energy of 1/2⟨111⟩{110} and 1/2⟨111⟩{112} edge dislocations in a b.c.c. transition metal: moments approach

A tight-binding type electronic theory is used to calculate the core structure and the core energy of 1/2⟨111⟩{110} and 1/2⟨111⟩{112} edge dislocations in a b.c.c. transition metal (α-Fe). The repulsive core–core interaction energies at short distances are simulated by the Born–Mayer potential. Comparisons and distinctions of the present results with respect to those obtained by using a pair-potential method are emphasized. It is shown that the electronic effects on the dislocation core calculation are important; there are systematic differences in the core structure between the present results and those obtained by using a pair-potential method. In addition, the Peierls stress of a 1/2⟨111⟩{112} edge dislocation, which is more stable than a 1/2⟨111⟩{110} edge dislocation, is calculated and compared with that of a screw dislocation obtained by the identical approach and with those of a pair-potential method.