Large thermoelectric power factors by opening the band gap in semimetallic Heusler alloys

Autor(en)

Fabian Garmroudi, Michael Parzer, Alexander Riss, Simon Beyer, Sergii Khmelevskyi, Takao Mori, Michele Reticcioli, Ernst Bauer

Abstrakt

Efficient thermoelectric devices are typically built from semiconducting materials since their band gap leads to an asymmetry in the continuum of energy-dependent charge transport necessary for a large Seebeck effect. Due to their low cost and excellent mechanical properties half- and full-Heusler compounds have emerged as promising candidates for various applications. Here, we demonstrate how the thermopower of semimetallic Fe₂VAl-based Heusler alloys can be significantly increased by transferring electronic states from within the pseudogap to higher energies. Density functional theory calculations predict that partial Ti and Si co-substitution in Fe₂V_1−xTi_xAl_1−ySi_y drives an opening of the pseudogap, that can be likewise achieved in Fe₂V_1−xTa_xAl_1−ySi_y. Consequently, our experimental measurements on these co-substituted systems reveal exceptionally large thermoelectric power factors (7.3 − 10.3 mWm⁻¹K⁻² near room temperature), as well as average power factors up to 4.6 mWm⁻¹K⁻² in the most pratical temperature range (293 − 573 K). With this work we set the course for a general and reliable way of boosting the thermoelectric performance of semimetallic Heusler alloys.

Organisation(en)

Computergestützte Materialphysik

Externe Organisation(en)

Technische Universität Wien, National Institute for Materials Science, University of Tsukuba

Journal

Materials Today Physics

Band

27

Anzahl der Seiten

7

DOI

https://doi.org/10.1016/j.mtphys.2022.100742

Publikationsdatum

10-2022

Peer-reviewed

Ja

ÖFOS 2012

103009 Festkörperphysik

ASJC Scopus Sachgebiete

Allgemeine Materialwissenschaften, Energy (miscellaneous), Physics and Astronomy (miscellaneous)

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/1ace7ca1-5392-4865-ba7e-469844097aaa