Thermoelectric Properties of Zintl Arsenide EuCuAs

• Published in: Journal of electronic materials Vol. 52; no. 5; pp. 3121 - 3131
• Main Authors: Nakamura, Naoto, Goto, Yosuke, Nakahira, Yuki, Miura, Akira, Moriyoshi, Chikako, Lee, Chul-Ho, Usui, Hidetomo, Mizuguchi, Yoshikazu
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2023; Springer Nature B.V
• Subjects: Arsenides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal structure; Electronics and Microelectronics; Fermi surfaces; First principles; Heat; Instrumentation; Intermetallic compounds; Materials Science; Mathematical analysis; Optical and Electronic Materials; Original Research Article; Phase transitions; Power factor; Preferred orientation; Radiation; Science; Seebeck effect; Sodium; Solid State Physics; Spectrum analysis; Switching (polarity); Temperature; Thermal conductivity; Thermoelectricity; Transport properties; Thermoelectric materials; transport properties; arsenide; electronic structure
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-023-10290-4

We demonstrate thermoelectric transport properties of Zintl arsenide EuCuAs. The crystal structure of EuCuAs (hexagonal P 63/ mmc space group) consists of a covalently-bonded honeycomb-type [CuAs] network sandwiched by nearly divalent Eu ions. Undoped EuCuAs exhibit the thermoelectric power factor of 1.2 and 0.4 mW/mK 2 at 673 K along directions perpendicular and parallel to the uniaxial hot-pressing direction, respectively. Despite the relatively high power factor, the dimensionless figure-of-merit is limited to 0.1 at 673 K due to the high lattice thermal conductivity, > 2.0 W/mK. In addition to the relatively high power factor, first-principles calculations predicted that, owing to a peculiar shape of the Fermi surface, heavy hole-doped EuCuAs with a hole concentration of > 1.5 × 10 21  cm –3 will exhibit axis-dependent conduction polarity, which enables us to construct transverse thermoelectric devices. We investigated the synthesis and thermoelectric transport properties of Eu 1– x Na x CuAs using sodium (Na) as a hole dopant, resulting in a hole concentration of 1.0 × 10 21  cm –3 . The absolute value of the Seebeck coefficient was decreased by Na-doping, as predicted by first-principles calculations, but no conduction polarity switching was observed. This may have resulted from an insufficient hole concentration and/or preferred orientation of the samples.