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Structural and electronic properties of the random alloy ZnSex S1-x

Sarkar, S and Eriksson, O and Sarma, DD and Marco, ID (2022) Structural and electronic properties of the random alloy ZnSex S1-x. In: Physical Review B, 105 (18).

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Official URL: https://doi.org/10.1103/PhysRevB.105.184201


In this article we employ density functional theory in the generalized gradient approximation to investigate the structural and electronic properties of the solid solution alloy ZnSexS1-x in the wurtzite structure. We analyzed the character of the bond lengths and angles at the atomic scale, using a supercell approach that does not impose any constraint on the crystal potential. We show that the bond lengths of pristine ZnS and ZnSe compounds are almost preserved between nearest neighbors, which is different from what would be anticipated if Vegard's law were valid at the atomic level. We also show that bond lengths start behaving in accordance with Vegard's law from the third shell of nearest neighbors onward, which in turn determines the average lattice parameters of the alloys determined by diffraction experiments. Fundamental building blocks around the anions are identified and are shown to be nonrigid but still volume preserving. Finally, the geometrical analysis is connected to the trend exhibited by the electronic structure, and in particular by the band gap. The latter is found to exhibit a small deviation from linearity with respect to the Se concentration, in accordance with available experimental data. By assuming a quadratic dependence, we can extract a bowing parameter and analyze various contributions to it with various calculations under selected constraints. The structural deformation in response to the doping process is shown to be the driving force behind the deviation from linearity. The difference in stiffness between ZnS and ZnSe is shown to play a key role in the asymmetric behavior of the bowing parameter observed in the S-rich and Se-rich regions. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html"Bibsam.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Atoms; Crystal atomic structure; Density functional theory; Electronic properties; Electronic structure; Energy gap; Historic preservation; HTTP; Zinc sulfide, Atomic scale; Bond lengths and angles; Bowing parameters; Density functional theory in the generalized gradient approximation; Nearest-neighbour; Random alloy; Solid solution alloy; Structural and electronic properties; Vegard's law; Wurtzite structure, II-VI semiconductors
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 29 Sep 2022 06:11
Last Modified: 29 Sep 2022 06:11
URI: https://eprints.iisc.ac.in/id/eprint/76818

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