Séminaire - Ruthenium oxide peculiarities probed by the Seebeck effect and prospection of novel thermoelectric chalcogenide materials assisted by machine learning - Florent Pawula

Lundi 23 janvier 2023 à 14 h 30

Sorbonne Université - Campus Pierre et Marie Curie - 4 Place Jussieu - 75005 PARIS - IMPMC - Barre 22-23 - 4e étage  - salle 401

Florent PAWULA   - Laboratory for Innovative Key Materials and Structures (LINK)

CNRS-Saint-Gobain-NIMS, IRL3629 Energy Material Design Group, Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS), Tsukuba, JAPAN

Abstract

In metallic ruthenium oxides, transport coefficients such as the Seebeck effect S can be described considering a coexistence of metallic carriers together with localized magnetic moment contributions enhancing S [1]. This work aimed to investigate the Seebeck coefficient in several ruthenium oxides presenting different electronic and magnetic backgrounds to better understand this coexistence effect. Different structures have been investigated: rutile, hollandites [2], R-type ferrites [3], and perovskites. These results have been compared to well-known SrRuO3 and Sr2RuO4 and provide evidence of a high T Seebeck coefficient protected from band structure considerations in ruthenium oxides.
Thermoelectric properties improvement of bulk chalcogenides is investigated through optimization of chemical composition, or process parameters, assisted by active learning coupled to Bayesian optimization [4, 5]. Modeling the properties at 673 K with computed descriptors of chemical elements only and the Random Forest algorithm has demonstrated relatively good performances for ternary and quaternary substituted-GeTe and also for Cu2ZnSnS4 kesterite. Preliminary results for proposed chemical compositions or process parameters targeting optimized Seebeck coefficient will be presented.

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[2] F. Pawula, S. H ́ebert, D. Pelloquin, and A. Maignan, J. Mater. Chem. C 7, 235106 (2021).
[3] F. Pawula, R. Daou, S. H ́ebert, D. Pelloquin, J. Juraszek, and A. Maignan, Phys. Rev. B 103,
235106 (2021).
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Yamauchi, J. Mater. Chem. A 8, 13532 (2020).
[5] G. Lambard, T. T. Sasaki, K. Sodeyama, T. Ohkubo, and K. Hono, Scr. Mater. 209 114341 (2022)