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Title: Boron arsenide phonon dispersion from inelastic x-ray scattering: Potential for ultrahigh thermal conductivity

Cubic boron arsenide (BAs) was predicted to have an exceptionally high thermal conductivity (k) ~2000 Wm -1K -1 at room temperature, comparable to that of diamond, based on first-principles calculations. Subsequent experimental measurements, however, only obtained a k of ~200 Wm-1K-1. To gain insight into this discrepancy, we measured phonon dispersion of single crystal BAs along high symmetry directions using inelastic x-ray scattering (IXS) and compared these with first-principles calculations. Based on the measured phonon dispersion, we have validated the theoretical prediction of a large frequency gap between acoustic and optical modes and bunching of acoustic branches, which were considered the main reasons for the predicted ultrahigh k. This supports its potential to be a super thermal conductor if very high-quality single crystal samples can be synthesized.
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  1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Div.; Univ. of Tennessee, Knoxville, TN (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Div.
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-06CH11357
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 22; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE; Virginia Polytechnic Institute and State University (Virginia Tech)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1335724; OSTI ID: 1397255