Atomic forces from Dirac-Kohn-Sham equations: Implementation in flexible (APW+lo/LAPW)+LO basis set

Abstract

Atomic forces formulation based on the Dirac-Kohn-Sham equation and flexible (APW+lo/LAPW)+LO basis set is presented. The formulation was implemented in the code FlapwMBPT and allows a user to easily switch between different basis functions of the augmentation type (APW or LAPW) and between different kind of local orbitals. Similar to the work (Phys.Rev.B 91 (2015) 035105), the implementation takes into account small discontinuities of the wave functions, density, and potential at the muffin-tin sphere boundaries. Applications to the materials with strong relativistic effects, such as $\alpha$-Uranium, PuCoGa${}_5$, and FePt, demonstrate robustness of the method. Comparison of the calculated forces with the ones obtained by numerical differentiation of the free energy shows close agreement with deviations about 0.1\% or less.

arXiv comment16 pages, 5 tables

References in corpus (4)

• Phonons and related properties of extended systems from density-functional perturbation theory
• Elimination of the linearization error in GW calculations based on the linearized augmented-plane-wave method
• Elimination of the linearization error and improved basis-set convergence within the FLAPW method
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Cited by in corpus (3)

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• Revealing fingerprints of valence excitons in x-ray absorption spectra with the Bethe-Salpeter equation