Thermoelectric performance of a metastable thin-film Heusler alloy

• Published in: Nature (London) Vol. 576; no. 7785; pp. 85 - 90
• Main Authors: Hinterleitner, B., Knapp, I., Poneder, M., Shi, Yongpeng, Müller, H., Eguchi, G., Eisenmenger-Sittner, C., Stöger-Pollach, M., Kakefuda, Y., Kawamoto, N., Guo, Q., Baba, T., Mori, T., Ullah, Sami, Chen, Xing-Qiu, Bauer, E.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2019; Nature Publishing Group
• Subjects: 639/4077/4107; 639/766/119/544; Alloys; Current carriers; Density functional theory; Dielectric films; Efficiency; Electric properties; Electrical resistivity; Electronic properties; Fermi level; Figure of merit; Heat conductivity; Heusler alloys; Humanities and Social Sciences; Laboratories; Magnetic alloys; Magnetron sputtering; Materials; Mathematical analysis; Metastable state; multidisciplinary; Physical properties; Power factor; Science; Science (multidisciplinary); Seebeck effect; Structure; Thermal conductivity; Thermal properties; Thermoelectric generators; Thermoelectric materials; Thin films; Austria
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-019-1751-9

Thermoelectric materials transform a thermal gradient into electricity. The efficiency of this process relies on three material-dependent parameters: the Seebeck coefficient, the electrical resistivity and the thermal conductivity, summarized in the thermoelectric figure of merit. A large figure of merit is beneficial for potential applications such as thermoelectric generators. Here we report the thermal and electronic properties of thin-film Heusler alloys based on Fe 2 V 0.8 W 0.2 Al prepared by magnetron sputtering. Density functional theory calculations suggest that the thin films are metastable states, and measurements of the power factor—the ratio of the Seebeck coefficient squared divided by the electrical resistivity—suggest a high intrinsic figure of merit for these thin films. This may arise from a large differential density of states at the Fermi level and a Weyl-like electron dispersion close to the Fermi level, which indicates a high mobility of charge carriers owing to linear crossing in the electronic bands. A high intrinsic thermoelectric figure of merit is found for a metastable thin-film Fe 2 V 0.8 W 0.2 Al Heusler alloy.