Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Frontiers of Electronic Structure Theory: Focus on Topology and Transport
(Joint session of DS, HL, MA, MM, O and TT organized by MM)

TT 21.5: Vortrag

Montag, 7. März 2016, 17:00–17:15, H51

High-pressure and nonlinear elastic response of solids: Example of carbon allotropes — •Pasquale Pavone, Rostam Golesorkhtabar, Stefan Kontur, and Claudia Draxl — Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, 12489 Berlin, Germany

As prototype materials showing strong nonlinear elastic behaviour, diamond and, more recently, layered carbon allotropes have attracted much attention. However, even the nonlinear elasticity of diamond is not completely clarified: Experimentally, nonlinear elastic constants of diamond were investigated only recently [1], showing significant discrepancies with theoretical results. Furthermore, the standard ab-initio reference calculation for diamond [2] is nowadays about 30 years old and needs to be updated in the light of current development of theory, numerical algorithms, and available computer power. Using the full-potential all-electron package T1lmttbnexciting [3], we perform a systematic ab-initio investigation of the nonlinear elastic properties of diamond, graphene monolayers, as well as simple-hexagonal and hexagonal graphite. We develope an extension of the T1lmttbnElaStic tool [4] for the determination of third-order elastic constants. From these results the pressure dependence of linear elastic constants is obtained and connected to dynamical quantities like the mode Grüneisen parameters.

[1] J.M. Lang et al., Phys. Rev. Lett. 106, 125502 (2011).

[2] O.H. Nielsen, Phys. Rev. B 34, 5808 (1986).

[3] A. Gulans et al., J. Phys.: Condens. Matter 26, 363202 (2014).

[4] R. Golesorkhtabar et al., Comp. Phys. Commun. 184, 1861 (2013).