Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 23: Methods in Computational Materials Modelling (methodological aspects, numerics)

MM 23.10: Talk

Wednesday, April 3, 2019, 12:45–13:00, H44

Implementation of stress tensor in LAPW method with emphasis on WIEN2k — •Kamal Belbase, Andreas Tröster, and Peter Blaha — Institute for Materials Chemistry, Vienna University of Technology, Vienna, Austria

The theoretical derivation and practical implementation of the stress tensor in all electron density functional theory (DFT) codes of the linearized augmented plane wave (LAPW) type is a long standing and demanding problem. Here we present some theoretical calculations and results for hydrostatic pressure as implemented in the WIEN2k code. Similar to the structure of force formulas, we derive the Hellmann-Feynman and Pulay contributions to the full stress tensor. Hydrostatic pressure is obtained by taking the trace of these terms. Comparison for our thereby calculated pressure to that computed from fits of the total energy using the Birch-Murnaghan's equation of state is presented for some cubic crystals.