Kinks in a/2<111> Screw Dislocation in Ta
CALIFORNIA INST OF TECH PASADENA MATERIALS AND PROCESS SIMULATION CENTER
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We study the structure and formation energy of kinks in 12a111 screw dislocations in metallic Tantalum using molecular dynamics with a first principles based many-body interatomic potential. In our study, four a3112 kinks are in a quadrupole arrangement in the simulation cell. We impose periodic boundary conditions in the directions perpendicular to 111 and fixed boundaries in the 111 direction. We find that two energetically equivalent, core configurations for the 12a111 dislocation lead to 8 distinguishable single kinks and 16 kink pairs. The different mismatches of the core configurations along 111 direction attribute to the variations in the formation energy for different type of kinks. Formation energies for all possible kinds of isolated single kinks and kink pairs have been determined. It was found that 0.730 eV was the lowest energy cost to form a kink pair in the a2111 screw dislocation in Ta.