Ab initio quasiharmonic equations of state for dynamically stabilized soft-mode materials
نویسندگان
چکیده
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 lowand 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.
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