Tunable Low-Temperature Thermoelectric Transport Properties in Layered CuCr(S1-xSex)2 System

H. Sajida Kousar, Divya Srivastava, Maarit Karppinen*, Girish C. Tewari*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
43 Downloads (Pure)

Abstract

We have characterized the layered CuCr(S,Se)2 system for the spin-polarized electronic band structures and low-temperature thermoelectric transport properties. The electronic band structure calculations reveal semiconducting behavior for CuCrS2, CuCr(S0.5Se0.5)2 and CuCrSe2 with an indirect bandgap of 0.42, 0.30 and 0.10 eV, respectively. The systematically decreased bandgap with increasing Se content is in line with the experimental observations showing a semiconductor-to-metal transition with increasing Se-substitution level in the CuCr(S1-xSex)2 system because of an increase in the charge carrier density. The p-type Seebeck coefficient shows a linear temperature dependence for the samples, like in degenerate semiconductors or metals. The remarkably large Seebeck coefficient even in metallic samples is due to a relatively large effective mass of charge carriers. As the thermal conductivity is intrinsically low owing to the layered crystal structure and is further decreased for the Se-substituted samples because of the increased phonon scattering from point defects, the thermoelectric characteristics are promising. The highest dimensionless figure-of-merit values were seen for the x=0.5 sample, e. g., 0.04 at 400 K.

Original languageEnglish
Article numbere202300079
JournalZeitschrift fur Anorganische und Allgemeine Chemie
Volume649
Issue number14
Early online date15 Jun 2023
DOIs
Publication statusPublished - 17 Jul 2023
MoE publication typeA1 Journal article-refereed

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