Effect of temperature on elastic constants, generalized stacking fault energy and dislocation cores in MgO and CaO

Temperature effect on the elastic constants and anisotropy of MgO and CaO are performed via first-principles approach combing the quasistatic approximation to elasticity and the quasiharmonic phonon approximation to thermal expansion. Generalized stacking fault energy curves at different temperature are also computed due to the importance for dislocation properties. The core structures of 1/2〈110〉{110} dislocations in MgO and CaO at different temperature are investigated within the improved Peierls–Nabarro dislocation theory using Foreman's method. It is found that the core width of dislocation increases with the increasing of temperature.