Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 54: Biomaterials and Biological Materials IV
MM 54.4: Vortrag
Donnerstag, 19. März 2015, 12:30–12:45, TC 006
Quantum-mechanical study of isotropic elastic properties of amorphous CaCO3 — •Martin Friák1,2, Gernot Pfanner2, David Holec3, Biyao Wu2,4, Helge Otto Fabritius2, Dierk Raabe2, and Jörg Neugebauer2 — 1Institute of Physics of Materials AS CR, v.v.i. Brno, Czech Republic — 2Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 3Montanuniversität Leoben, Leoben, Austria — 4RWTH Aachen University, Aachen, Germany
Nearly 80 % of all known animal species are protected by an exoskeleton formed by their cuticle. The cuticle represents a hierarchically structured multifunctional bio-composite based on chitin and proteins. Some groups like Crustacea reinforce the load-bearing parts of their cuticle with amorphous CaCO3 (ACC) in the form of nano-scopic particles. As these particles are too small to be probed experimentally, we use quantum-mechanical methods to determine the phase stability and elastic properties of ACC employing a supercell approach. Our study is focused on the identification of a suitable computational supercell to be used as a structural model for ACC. Amorphous CaCO3 lacks any periodic structural order and it is thus perfectly incompatible with the concept of computational supercells that are periodically repeated by inherent boundary conditions applied in most of computational programs. To address this challenge, we have tested a series of supercells with increasing number of atoms (from 30 to 1000) as structural models for ACC. Aiming at elastically isotropic properties of ACC, we analyze the converging size dependence of our results.