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arXiv · 2006.11003

On the structure and electronic properties of Fe$_2$V$_{0.8}$W$_{0.2}$Al thin films

E. Alleno·A. Berche·J. -C. Crivello·A. Diack Rasselio·P. Jund
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Abstract

A very large thermoelectric figure of merit ZT = 6 at 380 K has recently been reported in Fe$_2$V$_{0.8}$W$_{0.2}$Al under thin-film form (Hinterleitner et al., Nature 576 (2019) 85). Under this form, Fe$_2$V$_{0.8}$W$_{0.2}$Al experimentally crystallizes in a disordered A2 crystal structure, different from its bulk-form structure (L21). First principles calculations of the electronic structure performed in A2-Fe$_2$V$_{0.8}$W$_{0.2}$Al supercells generated by the Special Quasi-random Structure (SQS) method are thus reported here. These calculations unambiguously indicate that A2-Fe$_2$V$_{0.8}$W$_{0.2}$Al is a ferromagnetic metal at 0 K, displaying a small Seebeck coefficient at 400 K (< 30 microV/K). The present results contradict the scenario of the occurrence of a deep pseudo-gap at the Fermi level, previously invoked to justify ZT = 6 in Fe$_2$V$_{0.8}$W$_{0.2}$Al thin films.

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E. Alleno, A. Berche, J. -C. Crivello, A. Diack Rasselio, P. Jund. 2020-06-19. On the structure and electronic properties of Fe$_2$V$_{0.8}$W$_{0.2}$Al thin films. https://doi.org/10.1039/d0cp03738a

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