Electronic effect of kink in the edge dislocation in bcc iron: A first-principles study

Using the self-consistent discrete variational method based on density functional theory, we have investigated the electronic effect of kinks in the ⟨100⟩{010} and 1∕2⟨111⟩{011} edge dislocations (EDs) in bcc iron. Our calculations indicate that the kink formation energy is closely related to the type of ED. The EDs containing kinks are less stable than the corresponding EDs without kinks. Furthermore, we have calculated the structural energy, the interatomic energy, the local density of states, and the charge-density difference for these systems. We find that the bonds between the atoms along the slip direction in the kinked EDs are strengthened compared to those in the corresponding EDs. In addition, the calculations of the structural energy and the local density of states show that the atoms on the kink are more active than those in the corresponding ED. These results lead us to conclude that the kinks provide the structural and energetic preparation for the dislocation motion.