Computational materials science meets geophysics: dislocations and slip planes of MgO

We calculate the generalized stacking fault (GSF) surface energies of MgO using an interatomic potential that mimics accurately the ab initio energies, forces and stresses. Using the GSF in the framework of Peierls-Nabarro model, the properties of dislocations in MgO have been determined for its three main slip systems: {110}(11¯0), {100}(011) and {111}(11¯0). The obtained Peierls stresses are in good agreement with experimental data and yields the correct dominant slip system in MgO, namely {110}(11¯0) at low temperature and pressure.