Regensburg 2022 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 34: Data Driven Materials Science: Interatomic Potentials / Reduced Dimensions

MM 34.4: Vortrag

Donnerstag, 8. September 2022, 16:30–16:45, H45

Magnetic Atomic Cluster Expansion and application to Iron — •Matteo Rinaldi, Matous Mrovec, and Ralf Drautz — Interdisciplinary Centre for Advanced Materials Simulation (ICAMS)

The atomic cluster expansion (ACE)^[1,2,3] has proven to be a valuable tool to parametrize complex energy landscapes of pure elements and alloys. However, its application to potential energy surfaces determined also by additional degrees of freedom, such as magnetic moments, has been still lacking. In particular, ferromagnetic materials cannot be tackled with the original ACE formalism, where the single-site energies depend parametrically only on interatomic distances and chemical species, since these descriptors cannot distinguish between atoms with different magnetic moments. The solution of this issue was given theoretically by Drautz^[4], where the ACE formalism was extended to take into account additional labels of the atomic sites of scalar, vectorial and tensorial nature by including them in the definition of the atomic neighbor density. We have employed this formalism to parametrize a magnetic ACE for the prototypical ferromagnetic element Fe using a dataset of both collinear and non-collinear magnetic structures calculated with spin density functional theory. We will show that the new ACE model is able to describe correctly not only various magnetic phases of Fe at 0 K but also their finite temperature properties in good agreement with the reference ab-initio and experimental values.

[1] R. Drautz, Phys. Rev. B 99, 014104. [2] Y. Lysogorskiy et al., npj Comput Mater 7, 97 (2021). [3] A. Bochkarev et al., Phys. Rev. Materials 6, 013804. [4] R. Drautz, Phys. Rev. B 102, 024104.