Evidence of tuned anharmonicity in the thermoelectric material Cu2-xS

The mechanisms underlying the low thermal conductivity of Cu2-x(S, Se) have been attracting considerable attention. However, Cu defects in Cu2-x(S, Se) have been reported to lead to an unusual increase in lattice thermal conductivity, unlike the typical decrease caused by phonon scattering induced by point defects. We propose that this anomaly is caused by atomic anharmonicity. Here, we perform neutron diffraction on Cu defect-controlled Cu2-xS to reveal that as Cu defects increase, the volume of tetrahedral Cu distribution significantly shrinks and centralizes, suggesting a change in the potential around the Cu atom. We find that the degree of anharmonicity is highest in Cu2S and decreases with increasing Cu defects using one-particle potential fitting. This trend explains the increase in lattice thermal conductivity with increasing Cu defects. Our findings show that anharmonicity can be tuned through Cu defects, explaining the underlying mechanism of the anomalous increase in the lattice thermal conductivity. The origins of increased lattice thermal conductivity in Cu-defected Cu2-x(S, Se) remain unknown. Here, neutron diffraction performed on Cu defect-controlled Cu2-xS shows that the anharmonicity can be tuned through Cu defects.

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Publication Details

Journal
Communications Materials
Published
2025-04-01
DOI
https://doi.org/10.1038/s43246-025-00775-6
Citations
5
Primary Topic
Advanced Thermoelectric Materials and Devices
Type
article
Field-Weighted Citation Impact
2.59

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article

Evidence of tuned anharmonicity in the thermoelectric material Cu2-xS

Takashi Kamiyama, Masato Hagihala, Kazuhiro John Mori, Shinichi Itoh et al.
5 citations
Communications Materials
Advanced Thermoelectric Materials and Devices
2.59
article

Evidence of tuned anharmonicity in the thermoelectric material Cu2-xS

Takashi Kamiyama, Masato Hagihala, Kazuhiro John Mori, Shinichi Itoh, Yoshihisa Ishikawa, Seungyub Song, Deok‐Yong Cho, Kug‐Seung Lee, Sanghyun Lee, Takashi Saito, Shuki Torii
article en
5 citations

Abstract

The mechanisms underlying the low thermal conductivity of Cu2-x(S, Se) have been attracting considerable attention. However, Cu defects in Cu2-x(S, Se) have been reported to lead to an unusual increase in lattice thermal conductivity, unlike the typical decrease caused by phonon scattering induced by point defects. We propose that this anomaly is caused by atomic anharmonicity. Here, we perform neutron diffraction on Cu defect-controlled Cu2-xS to reveal that as Cu defects increase, the volume of tetrahedral Cu distribution significantly shrinks and centralizes, suggesting a change in the potential around the Cu atom. We find that the degree of anharmonicity is highest in Cu2S and decreases with increasing Cu defects using one-particle potential fitting. This trend explains the increase in lattice thermal conductivity with increasing Cu defects. Our findings show that anharmonicity can be tuned through Cu defects, explaining the underlying mechanism of the anomalous increase in the lattice thermal conductivity. The origins of increased lattice thermal conductivity in Cu-defected Cu2-x(S, Se) remain unknown. Here, neutron diffraction performed on Cu defect-controlled Cu2-xS shows that the anharmonicity can be tuned through Cu defects.

Communications MaterialsVol. 6(1)
Japan Atomic Energy Agency (JP), Pohang University of Science and Technology (KR), High Energy Accelerator Research Organization (JP), Chinese Academy of Sciences (CN), The Graduate University for Advanced Studies, SOKENDAI (JP), China Spallation Neutron Source (CN), Comprehensive Research Organization for Science and Society (JP), Institute of High Energy Physics (CN), Pohang Accelerator Laboratory, Jeonbuk National University (KR)
National Research Foundation, National Research Foundation of Korea, High Energy Accelerator Research Organization, Ministry of Science and ICT, South Korea
Openalex Percentile: Top 11%
Advanced Thermoelectric Materials and Devices
2.59
DOIOpen Access PDFOpenAlex
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