Regularity of thermal characteristics, thermoelectric properties of EuLnCuSe3 compounds (Ln = La–Lu)

• Published in: European physical journal plus 2024-05, Vol.139 (5), p.412, Article 412
• Main Authors: Habibullayev, Navruzbek N., Burkov, Aleksandr T., Novikov, Sergey V., Yurev, Ilya O., Aleksandrovskiy, Aleksandr S., Zakharova, Alena D., Shulaev, Nikita A., Denisenko, Yuriy G., Andreev, Oleg V.
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; Atomic; Complex Systems; Condensed Matter Physics; Decomposition reactions; Electrical resistivity; Enthalpy; Mathematical and Computational Physics; Molecular; Optical and Plasma Physics; P-type semiconductors; Physics; Physics and Astronomy; Polymorphism; Rare earth elements; Regular Article; Seebeck effect; Selenium; Semiconductors; Solid phases; Temperature dependence; Temperature effects; Theoretical
• ISSN: 2190-5444; 2190-5444
• DOI: 10.1140/epjp/s13360-024-05155-6

The temperatures and enthalpies of the decomposition of EuLnCuSe 3 compounds (Ln = La–Lu) are determined for the first time as functions of the Ln 3+ ionic radius (rLn 3+ ). The EuLnCuSe 3 compounds with Ln = La and Ce decompose in the course of a solid-phase reaction to form EuSe, Ln 2 Se 3 , and Cu 2− x Se, whereas those with Ln = Tb, Dy, Ho, Tm, and Lu melt incongruently to form EuSe and a melt, for example, T decay  = 1175 K and Δ H decay  = 2.66 kJ/mol for EuLaCuSe 3 , while T melt  = 1576 K and Δ H melt  = 2.69 kJ/mol for EuTbCuSe 3 . When plotted as functions of rLn 3+ , the temperatures of thermal effects of these compounds exhibit a periodic dependence and a tetrad effect. The temperature dependence of electrical resistivity and that of the Seebeck coefficient are measured from 300 to 600 K. It is shown that the studied compounds are p -type semiconductors with bandgaps ranging from 0.4 to ~ 1 eV.