Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 95: Novel Functional Materials II

HL 95.3: Vortrag

Freitag, 11. März 2016, 10:00–10:15, H10

Vibrational Properties of Thermoelectric Magnesium Silicides from First Principle: the role of explicit dopants — •Hagen - Henrik Kowalski, Luca Ghiringhelli, Christian Carbogno, and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin

Silicides, and particularly Mg₂Si, are simple, prototypical examples for thermoelectric materials and have thus recently attracted remarkable scientific interest. For this material class, most first-principles studies have so far focused on the structural stability, the electronic structure, and the electronic transport coefficients [1,2], viz. on how these properties can be tailored by doping. Little is however known about the effects of doping on the vibrational properties and the associated thermal conductivity, which are of similar importance for the thermoelectric efficiency. Therefore, we have systematically investigated how different dopants (Ca, Ge, Ag, etc.) affect the vibrational harmonic properties; anharmonic effects are analyzed within the quasi-harmonic approximation. We discuss the implications of our findings for the thermoelectric properties and how they can be utilized in a high-throughput framework.

[1] I. Opahle, G. K. H. Madsen, and R. Drautz, PCCP 14, 16197 (2012).

[2] S. Bhattacharya and G. K. H. Madsen, Phys. Rev. B 92, 085205 (2015).