I4/mmm phase of MgF2: An ab initio molecular dynamics study

Abstract

A constant pressure ab initio technique is applied in order to study the structural response of magnesium fluoride (MgF2) under the hydrostatic pressure up to 800 GPa. The orthorhombic-to-tetragonal phase transformation of MgF2 is obtained at 720 GPa. This phase transition is also analyzed from the total energy and enthalpy calculations, and it is found that this phase change should occur around 260 GPa. As far as we know, this tetragonal phase has not been obtained in any previous studies.