https://doi.org/10.1140/epjb/s10051-026-01136-z
Research - Condensed Matter
First-principles investigation of structural, electronic, thermoelectric, and elastic properties of perselenoborates QBSe3 (Q = Rb, Cs)
1
Laboratory of Materials for the Application and Valorization of Renewable Energies, Amar Telidji University, B.P. 37G, 03000, Laghouat, Algeria
2
Physics Department, Saad Dahlab Blida 1 University, B.P 270-Soumaa Road, Blida, Algeria
a
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Received:
8
November
2025
Accepted:
3
February
2026
Published online:
16
March
2026
Abstract
Structural, electronic, thermoelectric, and elastic properties of perselenoborate compounds QBSe3 (Q = Rb, Cs) have been investigated using density functional theory and semi-classical Boltzmann transport theory as implemented in the CRYSTAL17 program. Structural and elastic properties were calculated using the GGA-PBE functional for the exchange–correlation potential. The obtained results confirm the thermodynamic and mechanical stability of the compounds. Electronic structure calculations were performed using the GGA-PBE method, as well as the hybrid HSE06 and B3LYP functionals, revealing indirect semiconducting behavior. The hybrid functionals provided more accurate predictions of the band gaps. The density of states analysis confirms the covalent nature of the B–Se bonds. Thermoelectric properties, including Seebeck coefficient (S), electrical conductivity (σ), electronic thermal conductivity (κe), and power factor, were calculated based on electronic structures obtained using the HSE06 functional within the framework of the Boltzmann transport equations under the constant relaxation time approximation. They show a high Seebeck coefficient (2500–3000 μV/K at 300 K) and a remarkable electrical conductivity along the zz direction, particularly within the 400–600 K temperature range. The calculated electronic figure of merit (zTe) values approached unity, indicating excellent potential for efficient thermoelectric energy conversion. Additionally, the elastic constants satisfy mechanical stability criteria and demonstrate ductility, suggesting that RbBSe3 and CsBSe3 could be integrated into flexible thermoelectric devices. These findings highlight the novel combination of semiconducting, thermoelectric, and mechanically robust properties in perselenoborates, making them promising candidates for next-generation energy conversion technologies.
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© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
