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This content will become publicly available on June 29, 2019

Title: Two-channel model for ultralow thermal conductivity of crystalline Tl 3VSe 4

Solids with ultralow thermal conductivity are of great interest as thermal barrier coatings for insulation or thermoelectrics for energy conversion. However, the theoretical limits of lattice thermal conductivity (κ) are unclear. In typical crystals a phonon picture is valid, whereas lowest κ values occur in highly disordered materials where this picture fails and heat is supposedly carried by random walk among uncorrelated oscillators. Here in this paper we identify a simple crystal, Tl 3VSe 4, with a calculated phonon κ [0.16 Watts per meter-Kelvin (W/m-K)] one-half that of our measured κ (0.30 W/m-K) at 300 K, approaching disorder κ values, although Raman spectra, specific heat, and temperature dependence of κ reveal typical phonon characteristics. Adding a transport component based on uncorrelated oscillators explains the measured κ and suggests that a two-channel model is necessary for crystals with ultralow κ.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [2] ; ORCiD logo [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division; Naval Research Lab. (NRL), Washington, DC (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Science
Additional Journal Information:
Journal Volume: 360; Journal Issue: 6396; Journal ID: ISSN 0036-8075
Publisher:
AAAS
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1459275