Core structure and Peierls stress of edge and screw dislocations in TiN: A density functional theory study

A first-principles computational scheme was applied for studying edge and screw dislocations in non-elemental systems for the first time. For the case of TiN as a model system, we established the preferred slip systems for edge and screw dislocations, with a Burgers vector of a/2〈1 1¯ 0〉 on the {0 0 1}, {1 1 0} and {1 1 1} slip planes. The simulations adopted periodically repeating triclinic supercells containing a dipole of dislocations arranged such that periodicity can be maintained without imposition of large spurious elastic stresses. It was determined that the Peierls stress is the smallest for slip along the {1 1 0} plane, and largest for slip along the {0 0 1} plane, for both edge and screw dislocations. The dislocation core structures and the Peierls stress results are discussed and compared to those in a purely ionic MgO system.