Anharmonicity and atomic distribution of SnTe and PbTe thermoelectrics

Published

Journal Article

© 2014 American Physical Society. The structure and lattice dynamics of rock-salt thermoelectric materials SnTe and PbTe are investigated with single-crystal and powder neutron diffraction, inelastic neutron scattering (INS), and first-principles simulations. Our first-principles calculations of the radial distribution function in both SnTe and PbTe show a clear asymmetry in the first nearest-neighbor (1NN) peak, which increases with temperature, in agreement with recent experimental reports. We show that this peak asymmetry for the 1NN Sn-Te or Pb-Te bond results from large-amplitude anharmonic vibrations (phonons). No atomic off centering is found in our simulations. In addition, the atomic mean-square displacements derived from our diffraction data reveal stiffer bonding at the anion site, in good agreement with the partial phonon densities of states from INS and first-principles calculations. These results provide clear evidence for large-amplitude anharmonic phonons associated with the resonant bonding leading to the ferroelectric instability.

Full Text

Duke Authors

Cited Authors

  • Li, CW; Ma, J; Cao, HB; May, AF; Abernathy, DL; Ehlers, G; Hoffmann, C; Wang, X; Hong, T; Huq, A; Gourdon, O; Delaire, O

Published Date

  • December 29, 2014

Published In

Volume / Issue

  • 90 / 21

Electronic International Standard Serial Number (EISSN)

  • 1550-235X

International Standard Serial Number (ISSN)

  • 1098-0121

Digital Object Identifier (DOI)

  • 10.1103/PhysRevB.90.214303

Citation Source

  • Scopus