Temperature-Dependent Band Renormalization in CoSb3Skutterudites Due to Sb-Ring-Related Vibrations

Ziyu Wang, Jinyang Xi*, Jinyan Ning, Kai Guo, Bo Duan, Jun Luo, G. Jeffrey Snyder, Jiong Yang, Wenqing Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The temperature-dependent electronic structures in the thermoelectric semiconductor CoSb3 and its Yb-filled counterpart are studied by using the electron-phonon renormalization (EPR) method, considering both lattice expansion and phonon-induced atomic vibrations. The primary direct band gaps at the Γ-point for skutterudites decrease with increasing temperature, largely due to the increase in the energy level at the valance band maximum (VBM). The energy difference between the conduction band minimum (CBM) and second CB also decreases with temperature, inducing band convergence at high temperatures. The phonon vibrations of the Sb rings are responsible for these temperature-dependent electronic structures. Specifically, the four Sb-ring-related Ag phonon mode in CoSb3 plays a decisive role in causing the increase in the VBM with temperature and decrease in the primary band gap. The band convergence at high temperatures is due to the different responses to lattice vibrations of the second CB and the CBM for both systems. Our work sheds light on the relation between chemical bonds and phonon-assisted electronic structures.

Original languageEnglish (US)
Pages (from-to)1046-1052
Number of pages7
JournalChemistry of Materials
Volume33
Issue number3
DOIs
StatePublished - Feb 9 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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