We introduce a method for treating soft modes within the analytical framework of the quasiharmonic equation of state. The corresponding double-well energy-displacement relation is fitted to a functional form that is harmonic in both the low- and high-energy limits. Using density-functional calculations and statistical physics, we apply the quasiharmonic methodology to solid periclase (MgO). We predict the existence of a B1−B2 phase transition at high pressures and temperatures.
|Number of pages||14|
|Journal||Physical review B: Condensed matter and materials physics|
|Publication status||Published - 2002|
- MGSIO3 PEROVSKITE
- LOWER MANTLE