Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 47: Poster Session II
MM 47.21: Poster
Mittwoch, 14. März 2018, 18:30–19:45, Poster C
Ab-initio investigation of the elastic behavior of the ternary compounds CxSiyGe1−x−y in the cubic phase — •Tim Klose, Pasquale Pavone, and Claudia Draxl — Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, Germany
We investigate the set of all diamond-type structures of carbon, silicon, and germanium which can be represented in a cubic unit cell containing eight atoms.
Total-energy calculations are performed using density-functional theory as implemented in the full potential all-electron package T1lmttbnexciting [1]. In conjunction with T1lmttbnexciting, second-order elastic constants for all the considered structures are obtained using the T1lmttbnElaStic tool [2].
141 geometrically distinct initial configurations are obtained by occupying each site of an fcc diamond-like lattice with a C, Si, or Ge atom, of which the 48 most relevant configurations are selected. Then, second-order elastic constants are determined for each fully relaxed configuration by applying suitable distortions to the equilibrium structures.
We identify a clear distinction between three classes of configurations when analyzing the resulting equilibrium lattice and elastic constants. This classification can be correlated to the internal geometry and degree of symmetry of the corresponding configurations.
This project involved thousands of individual calculations and, thus,
required a careful analysis in order to extract significant findings from the generated data.
[1] A. Gulans et al., J. Phys.: Condens. Matter 26 (2014) 363202
[2] R. Golesorkhtabar et al., Comp. Phys. Commun. 184 1861 (2013)