Structural and thermal properties and the origin of the ultralow thermal conductivity in the defect stannite CuIn2Se4

Oluwagbemiga P. Ojo, Wilarachchige D.C.B. Gunatilleke, Hsin Wang, George S. Nolas

Research output: Contribution to journalArticlepeer-review

Abstract

Phase-pure CuIn2Se4, a ternary metal chalcogenide that forms in a disordered stannite crystal structure, was synthesized to investigate the structure thermal property relationships as well as reveal the origin of the ultralow thermal conductivity this material possesses over a large temperature range. Modeling of the temperature-dependent heat capacity and thermal conductivity revealed distinctive thermal properties and large lattice anharmonicity. Electron localization function calculations highlight the asymmetric bonding inherent to CuIn2Se4, which together with lattice anharmonicity directly impacts the thermal properties. Our findings reveal the specific atomic arrangement and bonding governing the thermal properties of this ternary metal chalcogenide. Our findings underscore the specific atomic arrangement and bonding governing the thermal properties in this ternary chalcogenide. This study advances the fundamental understanding of stannites, and our findings can be applied to these and other multinary metal chalcogenides of interest for applications where low thermal conductivity is desirable.

Original languageEnglish
Article number116518
JournalScripta Materialia
Volume258
DOIs
StatePublished - Mar 15 2025

Funding

H.W. acknowledges the support of the U.S. Department of Energy, Vehicle Technologies Office, Powertrain Materials Core Program and the International Energy Agency (IEA) Advanced Materials for transportation (AMT) Technology Collaboration Programme (TCP). Oak Ridge National Laboratory is managed by UT-Battelle LLC under contract DE-AC05000OR22725.

Keywords

  • Density functional theory (DFT)
  • Differential thermal analysis (DTA)
  • Thermal conductivity
  • X-ray diffraction (XRD)

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