Ab initioquasiharmonic equations of state for dynamically stabilized soft-mode materials

2002/03/29 by N. D. Drummond, Graeme J. Ackland, G. J. Ackland · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Chemical Physics Studies #High-pressure geophysics and materials #Quantum, superfluid, helium dynamics #cond-mat.mtrl-sci #cond-mat.stat-mech

paper · pdf · doi:10.1103/physrevb.65.184104

arxiv created 2002/03/29 · openalex publication_date 2002/04/25 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

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\ensuremath-B2 phase transition at high pressures and temperatures.

Citations

• Dynamical Theory of Crystal Lattices
• Self-interaction correction to density-functional approximations for many-electron systems
• Thermodynamics of Crystals
• Soft self-consistent pseudopotentials in a generalized eigenvalue formalism
• Iterative minimization techniques forab initiototal-energy calculations: molecular dynamics and conjugate gradients
• Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation

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