Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 9: Posters: Biotechnology and bioengineering
BP 9.1: Poster
Montag, 31. März 2014, 17:30–19:30, P3
Quantum-mechanical study of crystalline and amorphous calcite — Gernot Pfanner1, •Martin Friák1,2, Li-Fang Zhu1, Svetoslav Nikolov3, Anna Maria Janus1, Helge Otto Fabritius1, Pavlína Hemzalová1, Duancheng Ma1, Dierk Raabe1, Julia Huber4, Andreas Ziegler4, and Jörg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 2Institute of Physics of Materials AS CR, v.v.i. Brno, Czech Republic — 3Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria — 4Central Facility for Electron Microscopy, University of Ulm, Ulm, Germany
Arthropoda, that represent 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 calcite. We present a theoretical parameter-free quantum-mechanical study of the phase stability and structural and elastic properties of both crystalline and amorphous (ACC) calcite employing a supercell approach. Computational supercells employed as structural models for crystalline and amorphous calcite contain six and twenty CaCO3 formula units, respectively. Our comparative study shows that the density of amorphous calcite is lower than that of its crystalline form and that also the studied single-crystalline elastic constants are lower in case of ACC. Both findings are in qualitative agreement with available experimental data.