Temperature dependent effective potential method for accurate free energy calculations of solids

作者：Olle Hellman, Peter Steneteg, Igor A. Abrikosov, S. I. Simak · 发表于：Physical Review B · 年份：2013 · DOI：10.1103/physrevb.87.104111 · 被引用次数：646 · 研究领域：High-pressure geophysics and materials、Quantum, superfluid, helium dynamics、Nuclear Materials and Properties

We have developed a thorough and accurate method of determining anharmonic free energies, the temperature dependent effective potential technique (TDEP). It is based on ab initio molecular dynamics followed by a mapping onto a model Hamiltonian that describes the lattice dynamics. The formalism and the numerical aspects of the technique are described in detail. A number of practical examples are given, and results are presented, which confirm the usefulness of TDEP within ab initio and classical molecular dynamics frameworks. In particular, we examine from first principles the behavior of force constants upon the dynamical stabilization of the body centered phase of Zr, and show that they become more localized. We also calculate the phase diagram for ${}^{4}$He modeled with the Aziz et al. potential and obtain results which are in favorable agreement both with respect to experiment and established techniques.