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MM: Fachverband Metall- und Materialphysik
MM 36: Topical Session Electron Theory V
MM 36.5: Talk
Thursday, March 17, 2011, 15:30–15:45, IFW A
Non-scalar cluster expansions for arbitrary configuration dependent observables in advanced materials — •Sascha B. Maisel1, Nils Schindzielorz1, Karsten Durst2, and Stefan Müller1 — 1Hamburg University of Technology, Institute of Advanced Ceramics, Denickestrasse 15, 21073 Hamburg, Germany — 2Friedrich-Alexander Universität Erlangen-Nürnberg, Lehrstuhl für Werkstoffwissenschaften, Martensstrasse 5, 91056 Erlangen, Germany
We use DFT-based approaches to calculate both free energies and various quantities of technological relevance. These include bulk moduli, elastic constants, piezo-response tensors and dielectric constants of high-end materials like Ni-rich alloys and lead-free ferroelectrics. Based on the formalism of the cluster expansion [1] as realized in the UNCLE [2] package, it is possible to expand any configuration dependent observable like the formation enthalpy in terms of its many-body interactions. In this talk, we present several cluster expansions performed for multiple observables simultaneously. These types of cluster expansion each yield the formation enthalpy plus one or more of the aforementioned other quantities. This enables us to relate e.g an elastic constant of a structure with its chemical stability.
[1] J. M. Sanchez, F. Ducastelle, D. Gratias: Physica 128 A, 334, (1984)
[2] D. Lerch, O. Wieckhorst, G. L. W. Hart, R. Forcade, S. Müller: Modelling Simul. Mater. Sci. Eng. 17, 055003, (2009)