Quaternary chalcogenides continue to be of interest due to the variety of physical properties they possess, as well as their potential for different applications of interest. Investigations on materials with the sphalerite crystal structure have only recently begun. In this study we have synthesized sulfur-based sphalerite quaternary chalcogenides, including off-stoichiometric compositions, and investigated the temperature-dependent electronic, thermal and structural properties of these materials. Insulating to semiconducting transport is observed with stoichiometric variation, and analyses of heat capacity and thermal expansion revealed lattice anharmonicity that contributes to the low thermal conductivity these materials possess. We include similar analyses for CuZn 2 InSe 4 and compare these sphalerite quaternary chalcogenides to that of zinc blende binaries in order to fully understand the origin of the low thermal conductivity these quaternary chalcogenides possess.
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Structural diversity of CuZn 2 InSe 4 quaternary chalcogenides: electronic and phonon properties from first principles
First principles simulations are utilized to calculate the electronic and vibrational properties of several metastable structural phases of the CuZn 2 InSe 4 quaternary chalcogenide, including stanite, kesterite, primitive mixed CuAu, wurtzite-stanite, and wurtzite-kesterite lattices. We find that although each phase is formed by nearest cation-chalcogen bonds, the structural diversity due to cation and polyhedral arrangements has direct consequences in the electronic structure. The simulations further indicate that hybrid functionals are needed to account for the s–p and p–d orbital hybridization that is found around the Fermi level, which leads to much enhanced energy band gaps when compared with standard exchange-correlation approaches. We also find that the thermal conductivities for all phases are relatively low, and the main scattering channel comes from a low frequency optical band hybridized with acoustic phonons. Given that CuZn 2 InSe 4 is a material from a larger class of quaternary chalcogenides, other materials may exhibit similar electronic and vibrational properties, which may be useful for electronic and thermal management applications.
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- Award ID(s):
- 1748188
- PAR ID:
- 10423621
- Date Published:
- Journal Name:
- RSC Advances
- Volume:
- 12
- Issue:
- 41
- ISSN:
- 2046-2069
- Page Range / eLocation ID:
- 26648 to 26656
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d2ra04261d
