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Nanophase separation in CoSb-based half-Heusler thermoelectrics : A multiscale simulation study

Titelangaben

Miranda Mena, Joaquin ; Schoberth, Heiko G. ; Gruhn, Thomas ; Emmerich, Heike:
Nanophase separation in CoSb-based half-Heusler thermoelectrics : A multiscale simulation study.
In: Physica Status Solidi A. Bd. 213 (2016) Heft 3 . - S. 706-715.
ISSN 1521-396X
DOI: https://doi.org/10.1002/pssa.201532457

Volltext

Link zum Volltext (externe URL): Volltext

Abstract

If cooled down from high temperatures, some half-Heusler alloys based on CoTiSb show a spontaneous phase separation into coexisting domains. In thermoelectric applications, this domain structure is beneficial for the efficiency because it reduces the lattice thermal conductivity, which increases the figure of merit. For this reason, it is of great relevance to understand the details of the demixing phenomenon. We combine density functional theory, Monte Carlo simulations, and mean field calculations in order to investigate the demixing behavior of CoTi1−xZxSb with Z= Sc, V, Cr, Mn, Fe, Cu. Based on the calculations we present phase diagrams, which provide the coexistence region of the materials. Density functional theory results show that for low temperatures, demixed states are more stable than mixed ones. With the help of an ab initio-based cluster expansion of the configurational energy, we can perform mean field calculations and Monte Carlo simulations to study half-Heusler alloys at higher temperature on a larger scale. With the mean field calculations, the coexistence region and the spinodal can be determined for regions far from the critical point. The Monte Carlo simulations help to improve the coexistence lines and provide insights into structures formed in alloys that are quenched into the coexistence region.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Keywords: ab initio calculations; Cluster expansion; CoTiSb; domains; half-Heusler alloys; thermoelectric materials
Institutionen der Universität: Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Material- und Prozesssimulation
Fakultäten > Fakultät für Ingenieurwissenschaften > Ehemalige Professoren > Lehrstuhl Material- und Prozesssimulation - Univ.-Prof. Dr.-Ing. Heike Emmerich
Fakultäten
Fakultäten > Fakultät für Ingenieurwissenschaften
Fakultäten > Fakultät für Ingenieurwissenschaften > Ehemalige Professoren
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 530 Physik
500 Naturwissenschaften und Mathematik > 540 Chemie
600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften
Eingestellt am: 14 Mär 2016 09:52
Letzte Änderung: 30 Aug 2022 10:46
URI: https://eref.uni-bayreuth.de/id/eprint/31724