Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 44: Developement of Calculation Methods II
MM 44.7: Vortrag
Mittwoch, 20. März 2024, 17:30–17:45, C 264
Sampling-free computation of finite temperature material properties in isochoric and isobaric ensembles using the mean-field anharmonic bond model — •Raynol Dsouza1, Marvin Poul1, Liam Huber2, Thomas D. Swinburne3, and Jörg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, 40327, Germany — 2Grey Haven Solutions, Victoria, BC, Canada — 3Aix-Marseille Universite, CNRS, CINaM UMR 7325, Campus de Luminy, Marseille 13288, France
The recently introduced mean-field anharmonic bond model has shown remarkable accuracy in predicting finite temperature free energies for certain potential models of fcc crystals without thermodynamic sampling. In this work, we extend the model to treat modern machine learning potentials in both isochoric and isobaric ensembles. Testing against molecular dynamics simulations of Al and Cu, we find meV/atom accuracy in free energies up to the melting temperature under typical operating pressures, with similar accuracy for the thermal expansion. Our sampling-free estimation is universally superior to the quasi-harmonic approximation for a computational cost that is nearly two orders of magnitude lower and many orders of magnitude more efficient than thermodynamic integration. We discuss applications of the method in modern computational materials science workflows.
Keywords: Thermodynamics; Anharmonic lattice dynamics; Classical statistical mechanics; Mean-filed theory