Net negative contributions of free electrons to the thermal conductivity of NbSe3nanowires

Zhiliang Pan, Lin Yang, Yi Tao, Yanglin Zhu, Ya Qiong Xu, Zhiqiang Mao, Deyu Li

Research output: Contribution to journalArticlepeer-review

Abstract

Understanding transport mechanisms of electrons and phonons, two major energy carriers in solids, are crucial for various engineering applications. It is widely believed that more free electrons in a material should correspond to a higher thermal conductivity; however, free electrons also scatter phonons to lower the lattice thermal conductivity. The net contribution of free electrons has been rarely studied because the effects of electron-phonon (e-ph) interactions on lattice thermal conductivity have not been well investigated. Here an experimental study of e-ph scattering in quasi-one-dimensional NbSe3 nanowires is reported, taking advantage of the spontaneous free carrier concentration change during charge density wave (CDW) phase transition. Contrary to the common wisdom that more free electrons would lead to a higher thermal conductivity, results show that during the depinning process of the condensed electrons, while the released electrons enhance the electronic thermal conductivity, the overall thermal conductivity decreases due to the escalated e-ph scattering. This study discloses how competing effects of free electrons result in unexpected trends and provides solid experimental data to dissect the contribution of e-ph scattering on lattice thermal conductivity. Lastly, an active thermal switch design is demonstrated based on tuning electron concentration through electric field.

Original languageEnglish (US)
Pages (from-to)21131-21138
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume22
Issue number37
DOIs
StatePublished - Oct 7 2020

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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