Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 4: Carbon: Diamond, Nanotubes, and Graphene
HL 4.12: Vortrag
Montag, 14. März 2011, 13:15–13:30, POT 251
Nonlinear elasticity of graphene and other hexagonal carbon allotropes — •Pasquale Pavone1,2, Rostam Golesorkhtabar1,2, Jürgen Spitaler1,2, and Claudia Ambrosch-Draxl1 — 1Atomistic Modelling and Design of Materials, University of Leoben, Austria — 2Materials Center Leoben, Forschung Gmbh, Leoben, Austria
In this work, we present a first-principles study of the linear and nonlinear elastic properties of diamond, graphene monolayers, as well as simple-hexagonal, hexagonal, and rhombohedral graphite. Calculations are performed using the pseudo-potential density-functional-theory code Quantum ESPRESSO (QE) and both the local-density and generalized-gradient approximations for the exchange-correlation energy. For each system, the Lagrangian stress tensor is calculated for distorted structures defined by given values of the Lagrangian strain. The investigation of the stress vs. strain curves allows the determination of second and higher-order elastic constants. The results we have obtained for elastic constants at different orders are discussed in comparison with experiment and previous calculations, and with results achieved using the full-potential LAPW codes WIEN2k and exciting. In particular, we consider the issue of numerical accuracy in the ab-initio calculation of higher-order elastic constants. Furthermore, we investigate the role of van-der-Waals interlayer interactions by using the vdW-DF extension to the QE software package.