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Yu Y, Zhou C, Ghosh T, Schön CF, Zhou Y, Wahl S, Raghuwanshi M, Kerres P, Bellin C, Shukla A, Cojocaru-Mirédin O, Wuttig M. Doping by Design: Enhanced Thermoelectric Performance of GeSe Alloys Through Metavalent Bonding. Adv Mater 2023; 35:e2300893. [PMID: 36920476 DOI: 10.1002/adma.202300893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/25/2023] [Indexed: 05/12/2023]
Abstract
Doping is usually the first step to tailor thermoelectrics. It enables precise control of the charge-carrier concentration and concomitant transport properties. Doping should also turn GeSe, which features an intrinsically a low carrier concentration, into a competitive thermoelectric. Yet, elemental doping fails to improve the carrier concentration. In contrast, alloying with Ag-V-VI2 compounds causes a remarkable enhancement of thermoelectric performance. This advance is closely related to a transition in the bonding mechanism, as evidenced by sudden changes in the optical dielectric constant ε∞ , the Born effective charge, the maximum of the optical absorption ε2 (ω), and the bond-breaking behavior. These property changes are indicative of the formation of metavalent bonding (MVB), leading to an octahedral-like atomic arrangement. MVB is accompanied by a thermoelectric-favorable band structure featuring anisotropic bands with small effective masses and a large degeneracy. A quantum-mechanical map, which distinguishes different types of chemical bonding, reveals that orthorhombic GeSe employs covalent bonding, while rhombohedral and cubic GeSe utilize MVB. The transition from covalent to MVB goes along with a pronounced improvement in thermoelectric performance. The failure or success of different dopants can be explained by this concept, which redefines doping rules and provides a "treasure map" to tailor p-bonded chalcogenides.
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Affiliation(s)
- Yuan Yu
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Chongjian Zhou
- State Key Laboratory of Solidification Processing, and Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Tanmoy Ghosh
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Carl-Friedrich Schön
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Yiming Zhou
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Sophia Wahl
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Mohit Raghuwanshi
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Peter Kerres
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
- PGI 10 (Green IT), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
| | - Christophe Bellin
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, MNHN, 4 Place Jussieu, Paris, F-75005, France
| | - Abhay Shukla
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, MNHN, 4 Place Jussieu, Paris, F-75005, France
| | - Oana Cojocaru-Mirédin
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
| | - Matthias Wuttig
- Institute of Physics (IA), RWTH Aachen University, Sommerfeldstraße 14, 52074, Aachen, Germany
- PGI 10 (Green IT), Forschungszentrum Jülich GmbH, 52428, Jülich, Germany
- Jülich - Aachen Research Alliance (JARA-FIT and JARA-HPC), RWTH Aachen University, 52056, Aachen, Germany
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