Density Functional Theory Investigation of Physical Properties of KCrZ (Z = S, Se, Te) Half‐Heusler Alloys

• Published in: physica status solidi (b) 2021-10, Vol.258 (10), p.n/a
• Main Authors: Telfah, Ahmad, Sâad Essaoud, Saber, Baaziz, Hakim, Charifi, Zoulikha, Alsaad, Ahmad Mohammad, A. Ahmad, Mais Jamil, Hergenröder, Roland, Sabirianov, Renat
• Format: Article
• Language: English
• Subjects: computational physics; density functional theory; electronic structure; half metallic; Heusler alloys; Seebeck coefficient; thermoelectric and thermal properties
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.202100039

A theoretical investigation of the electronic structure and the magnetic and thermoelectric (TE) properties of KCrS, KCrSe, and KCrTe half‐Heusler alloys is studied. The most stable structural−magnetic configuration is identified, taking into consideration three types of possible atomic arrangements. The results indicate that KCrZ (Z = S, Se, Te) alloys are completely spin‐polarized half‐metallic ferromagnets in their ground state. Band structure calculations demonstrate that all compounds exhibit large bandgaps in the localized minority spin channel with a significant magnetic moment and high spin polarization (100%). The temperature dependence of the TE properties, such as the Seebeck coefficient and the electrical and thermal conductivity coefficients, is discussed and investigated using the semi‐local Boltzmann transport theory in the temperature range 250–1000 K. The quasiharmonic model is implemented to investigate and analyze the thermal parameters. In particular, thermal expansion coefficient, thermal conductivity, Debye temperature, specific heat capacity at constant volume, and entropy of the three novel half‐Heusler alloys are calculated and interpreted. The KCrZ (Z = S, Se, and Te) show a strong half‐metallic behavior with a large magnetic moment of 5 μB. The electronic properties show that these alloys behave as metals in majority direction, whereas in minority directions, they behave as semiconductors. The obtained thermoelectric modulus indicates that KCrZ (Z = S, Se, and Te) half‐Heusler alloys are potential candidates for many thermoelectric applications.