Convergence of multi-valley bands as the electronic origin of high thermoelectric performance in CoSb3 skutterudites

Yinglu Tang, Zachary M. Gibbs, Luis A. Agapito, Guodong Li, Hyun Sik Kim, Marco Buongiorno Nardelli, Stefano Curtarolo, G. Jeffrey Snyder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

333 Scopus citations

Abstract

Filled skutterudites RxCo4Sb12 are excellent n-type thermoelectric materials owing to their high electronic mobility and high effective mass, combined with low thermal conductivity associated with the addition of filler atoms into the void site. The favourable electronic band structure in n-type CoSb3 is typically attributed to threefold degeneracy at the conduction band minimum accompanied by linear band behaviour at higher carrier concentrations, which is thought to be related to the increase in effective mass as the doping level increases. Using combined experimental and computational studies, we show instead that a secondary conduction band with 12 conducting carrier pockets (which converges with the primary band at high temperatures) is responsible for the extraordinary thermoelectric performance of n-type CoSb3 skutterudites. A theoretical explanation is also provided as to why the linear (or Kane-type) band feature is not beneficial for thermoelectrics.

Original languageEnglish (US)
Pages (from-to)1223-1228
Number of pages6
JournalNature materials
Volume14
Issue number12
DOIs
StatePublished - Dec 2015

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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