Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 52: Methods in Computational Materials Modelling (methodological aspects, numerics)

MM 52.4: Talk

Thursday, March 15, 2018, 11:00–11:15, TC 006

Accurate free energies from ab initio: Applications of the TU-TILD technique — •Xi Zhang¹, Dominique Korbmacher¹, Lifang Zhu¹, Albert Glensk¹, Andrew Duff³, Fritz Körmann^1,2, Blazej Grabowski¹, and Jörg Neugebauer¹ — ¹Max-Planck-Institut für Eisenforschung GmbH, D-40237, Düsseldorf, Germany — ²Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft, Netherlands — ³Scientific Computing Department, STFC Daresbury Laboratory, Hartree Centre, Warrington, UK

Calculations of free energies have been long pursued to predict and understand many important phenomena in materials, e.g., thermodynamic properties, defect properties, or phase transitions. Computing free energies with sufficient accuracy fully from ab initio is a demanding challenge requiring special methodological techniques. Based on density functional theory, the recently developed TU-TILD (two-stage upsampled thermodynamic integration using Langevin dynamics) [Phys. Rev. B 91, 214311 (2015)] technique provides a very efficient framework retaining the desired accuracy in the free energies, capturing in particular explicit anharmonicity. We show the efficiency and accuracy of the TU-TILD technique by focussing on stacking fault Gibbs energies. Successful extensions to point defect Gibbs energies, dynamically unstable phases, phonon lifetimes and liquid free energies within the TOR-TILD technique will be briefly highlighted.