Berlin 2012 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 39: Topical Session Theory meets Experiment IV - Batteries, Thermoelectrics and Thermal Barrier Coatings

MM 39.3: Vortrag

Mittwoch, 28. März 2012, 17:00–17:15, TC 006

First Principles Study of Thermoelectric Boron-Carbide Compounds — •Karsten Rasim, Christian Carbogno, and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4–6, 14195 Berlin

A significant fraction of the world energy consumption goes into “waste heat”. For recovering some of it one needs to develop significantly more efficient thermoelectric (TE) materials then what is known to date. Boron-carbide based compounds have recently been proposed as promising candidates for high temperature applications, in particular due to the fact that their TE properties can be remarkably altered by adding a large variety of rare earth or transition metals [1]. In this work, we employ density functional theory (DFT) to assess the electronic and atomistic structure of such modified boron-carbide compounds. Thereby, we are able to identify the elemental mechanisms that determine the properties of these materials, e.g., the sign of the majority charge carrier [1]. We further discuss how the systematic underestimation of the band gap with approximate exchange-correlation (XC) functionals [2] affects our results by comparing experimental data and calculations performed at various levels of theory, i.e., with LDA, GGA, and hybrid XC functionals. In particular, we comment on the implications of these findings with respect to the computational assessment of TE properties [3].
[1] T. Mori and T. Nishimura, J. Sol. State Chem. 179, 2908 (2006).
[2] P. Rinke et al., New J. Phys. 7, 126 (2005).
[3] P. Boulet et al., Comp. Mat. Sci. 50, 847 (2011).