Ultrahigh zT from strong electron-phonon interactions and a low-dimensional Fermi surface

V. K. Ranganayakulu, Te Hsien Wang, Cheng Lung Chen*, Angus Huang, Ma Hsuan Ma, Chun Min Wu, Wei Han Tsai, Tsu Lien Hung, Min Nan Ou, Horng Tay Jeng*, Chih Hao Lee, Kuei Hsien Chen, Wen Hsien Li, Madison K. Brod, G. Jeffrey Snyder, Yang Yuan Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The outstanding thermoelectric performance of GeTe has attracted significant attention in the research community in recent years. However, many of the underlying physical mechanisms that contribute to GeTe's exceptionally high figure of merit (zT) remain not fully understood. In this study, an Sb-Bi codoped GeTe single crystal (Ge0.86Sb0.08Bi0.06)Te with an ultrahigh zT of 2.7 at 700 K and a record high device zT of 1.41 in the temperature range of 300-773 K was synthesized and investigated. The ultrahigh zT is attributed to the extremely low lattice thermal conductivity induced by strong electron-phonon (EP) interactions as revealed by the experimentally observed Kohn anomaly, through inelastic neutron scattering (INS) measurements. First-principles calculations further demonstrate that the remarkable EP interaction arises from the Fermi surface nesting featured in a one-dimensional (double-walled) topology. Our finding unravels the ultrahigh-zT mechanism in GeTe-based materials, serving as an inspiring guide toward high thermoelectric performance.

Original languageEnglish (US)
Pages (from-to)1904-1915
Number of pages12
JournalEnergy and Environmental Science
Volume17
Issue number5
DOIs
StatePublished - Jan 27 2024

Funding

We acknowledge helpful discussions with Prof. Mei-Yin Chou on the interpretation of neutron data. This work was financially supported by Ministry of Science and Technology (MOST), Taiwan, Grant No. MOST 110-2112-M-001-080, MOST 109-2112-M-001-047, MOST 109-2112-M-007-034-MY3, MOST 111-2112-M-001-080, NSTC 112-2112-M-131-002-MY3, NSTC 109-2112-M-005-014-MY3, NSTC 112-2112-M-007-034-MY3, NSTC 112-2112-M-001-076, and the research grant from Academia Sinica and iSNR-NCHU-MOE, AS-SS-109-01-110. H.T.J. also thanks support from NCHC, CINCNTU, AS-iMATE-111-12, and CQT-NTHU-MOE, Taiwan.

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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