Band convergence in the non-cubic chalcopyrite compounds Cu2MGeSe4

Wolfgang G. Zeier*, Hong Zhu, Zachary M. Gibbs, Gerbrand Ceder, Wolfgang Tremel, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

Inspired by recent theoretical predictions on band convergence in the tetragonal chalcopyrite compounds, we have explored the influence of the crystal structure on the transport and bandstructure of different quaternary chalcopyrites. In theory, a changing lattice parameter ratio of c/2a towards unity should lead to band convergence due to a more cubic and higher symmetry structure. In accordance with this prediction, the different solid solutions explored in this manuscript show a significant impact on the electronic transport depending on the ratio of the lattice parameters. An increasing lattice parameter ratio results in an increase of the carrier effective masses which can be explained by converging bands, ultimately leading to an increase of the power factor and thermoelectric figure of merit in the class of non-cubic chalcopyrite compounds Cu2MGeSe4. However, the calculations via density functional theory show that the critical value of c/2a, where band convergence occurs, will be different from unity due to symmetry and chemical influences on the band structure.

Original languageEnglish (US)
Pages (from-to)10189-10194
Number of pages6
JournalJournal of Materials Chemistry C
Volume2
Issue number47
DOIs
StatePublished - Dec 21 2014

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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