High Pressure Effects on the Properties of < 110 > {001} Dislocation in Superconducting ZnCNi3 and MgCNi3 Determined from First Principles Calculations Combined with an Improved Peierls-Nabarro Equation

摘要

We have employed an improved Peierls-Nabarro (P-N) equation considering the discreteness effect of crystals to study the properties of 1/2 < 110 > dislocation in the (001) plane in cubic anti-perovskites type superconducting materials ZnCNi3 and MgCNi3 under different pressure. The generalized-stacking-fault energy (GSFE) curves were calculated by using first-principles density functional theory (DFT). The core structures and Peierls stress of the screw, mixed, and edge dislocation in the pressure range 0-50 GPa have been systematically researched by solving the modified P-N dislocation equation combining with calculation of GSFE curves. With increasing pressure, the Peierls stress increases, but the core width decreases, and the Peierls stress of mixed dislocations is in the region between screw and edge dislocations. Finally, the electronic structure further reveals the underlying mechanisms for the effects of dislocation on the electronic properties.