Dresden 2011 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 46: Mechanical Properties III
MM 46.11: Vortrag
Freitag, 18. März 2011, 13:00–13:15, IFW D
Ab-initio calculation of second- and third-order elastic constants — •Rostam Golesorkhtabar1,2, Pasquale Pavone1,2, Jürgen Spitaler1,2, Peter Puschnig1, and Claudia Ambrosch-Draxl1 — 1Chair of Atomistic Modelling and Design of Materials, University of Leoben, Austria — 2Materials Center Leoben, Forschung Gmbh, Austria
Elastic properties of solids play a key role in materials science and technology. Various mechanical and thermodynamical properties are directly connected to elastic constants of different orders. In particular, the analysis of nonlinear quantities such as the third-order elastic constants (TOEC) gives a direct way of exploring the effect of anharmonicity of the lattice potential. In this work, we present a framework for the first-principles calculation of both second-order elastic constants (SOEC) and TOEC. We have implemented their calculation in the ElaStic package. The latter is now able to evaluate the full SOEC and TOEC for any crystal structure from ab-initio total-energy and/or stress calculations. We have applied ElaStic to obtain SOEC for one representative crystal of the 9 different symmetry classes. Furthermore, we calculate the TOEC and pressure dependence of the SOEC for diamond, hexagonal Mg, and rhombohedral Al2O3. The calculations are performed using total energy and stress data from the FP-LAPW codes WIEN2k and exciting and the pseudo-potential code Quantum ESPRESSO. Our results demonstrate the ElaStic describes with high precision linear and nonlinear elastic constants for materials characterized by different chemical bonding.