Thermoelectric properties of SbXY (X = Se, Te; Y = Br, I) Janus layers

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Main Authors: Vallinayagam, M., Sudheer, A. E., Kumar, A., Tejaswini, G., Posselt, M., Kamal, C., Murali, D., Zschornak, M.
Format: Preprint
Published: 2025
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author Vallinayagam, M.
Sudheer, A. E.
Kumar, A.
Tejaswini, G.
Posselt, M.
Kamal, C.
Murali, D.
Zschornak, M.
author_facet Vallinayagam, M.
Sudheer, A. E.
Kumar, A.
Tejaswini, G.
Posselt, M.
Kamal, C.
Murali, D.
Zschornak, M.
contents We report a comprehensive investigation of the thermoelectric properties of SbXY (X = Se, Te; Y = Br, I) Janus layers (JL) using spin-polarized first-principles calculations. Ab initio molecular dynamics confirm that the 1T phase ($Pm31$) remains stable up to 1000 K, excluding any phase transitions. The calculated mean-square displacement further evidences the structural robustness. The thermal conductivity is strongly suppressed in Br-containing layers due to enhanced Froehlich interactions between optical and acoustic phonons. Electronic structure calculations reveal indirect band gaps of 1.1 to 1.3 eV, with valence and conduction bands dominated by the $p$-orbitals of halogen/chalcogen and of Sb, respectively. The carrier effective mass highlights anisotropic transport with lighter electrons being more mobile, while holes dominate the power factor, which attains values on the order of mW/mK$^2$. Direction-dependent transport indicates superior thermoelectric performance along the $xx$ direction, with negligible contribution along $yy$. The Figure of Merit reaches 0.6 at 1000 K in hole-doped SbSeBr, demonstrating strong potential for high-temperature applications. Our results reveal that the SbXY JLs, particularly SbSeBr, emerge as promising candidates for next-generation thermoelectric devices at elevated temperatures.
format Preprint
id arxiv_https___arxiv_org_abs_2512_12626
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Thermoelectric properties of SbXY (X = Se, Te; Y = Br, I) Janus layers
Vallinayagam, M.
Sudheer, A. E.
Kumar, A.
Tejaswini, G.
Posselt, M.
Kamal, C.
Murali, D.
Zschornak, M.
Materials Science
We report a comprehensive investigation of the thermoelectric properties of SbXY (X = Se, Te; Y = Br, I) Janus layers (JL) using spin-polarized first-principles calculations. Ab initio molecular dynamics confirm that the 1T phase ($Pm31$) remains stable up to 1000 K, excluding any phase transitions. The calculated mean-square displacement further evidences the structural robustness. The thermal conductivity is strongly suppressed in Br-containing layers due to enhanced Froehlich interactions between optical and acoustic phonons. Electronic structure calculations reveal indirect band gaps of 1.1 to 1.3 eV, with valence and conduction bands dominated by the $p$-orbitals of halogen/chalcogen and of Sb, respectively. The carrier effective mass highlights anisotropic transport with lighter electrons being more mobile, while holes dominate the power factor, which attains values on the order of mW/mK$^2$. Direction-dependent transport indicates superior thermoelectric performance along the $xx$ direction, with negligible contribution along $yy$. The Figure of Merit reaches 0.6 at 1000 K in hole-doped SbSeBr, demonstrating strong potential for high-temperature applications. Our results reveal that the SbXY JLs, particularly SbSeBr, emerge as promising candidates for next-generation thermoelectric devices at elevated temperatures.
title Thermoelectric properties of SbXY (X = Se, Te; Y = Br, I) Janus layers
topic Materials Science
url https://arxiv.org/abs/2512.12626