An efficient way of increasing the total entropy of mixing in high-entropy-alloy compounds: a case of NaCl-type (Ag,In,Pb,Bi)Te1−xSex (x = 0.0, 0.25, 0.5) superconductors

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 49; no. 26; pp. 9118 - 9122
• Main Authors: Yamashita, Aichi, Jha, Rajveer, Goto, Yosuke, Matsuda, Tatsuma D, Aoki, Yuji, Mizuguchi, Yoshikazu
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2020
• Subjects: Alloying effects; Alloying elements; Critical field (superconductivity); Crystallography; High entropy alloys; Lead; Silver; Superconductivity; Synthesis; Temperature dependence
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d0dt01880e

We propose an efficient way of increasing the entropy of mixing in high-entropy-alloy-type compounds, which can be achieved by multi-site alloying. As an example of this concept, we report the synthesis and observation of polycrystalline samples of new high-entropy-alloy-type metal chalcogenides (Ag,In,Pb,Bi)Te1−xSex (x = 0.0, 0.25, and 0.5) with a NaCl-type structure. The samples were synthesized using high pressure synthesis. Superconductivity with transition temperatures of 2.7, 2.5, and 2.0 K was observed with x = 0.0, 0.25, and 0.5, respectively. To investigate the multi-site alloying effect on the entropy of mixing (ΔSmix) for the examined samples, we calculated the total ΔSmix for two crystallographic sites. For the samples with x = 0.25 and 0.5, ΔSmix reaches 1.89R and 2.00R, respectively, which exceed the ΔSmix of 1.79R for a simple (single-site) high-entropy alloy containing six different elements.