Phonon Self-Energy and Origin of Anomalous Neutron Scattering Spectra in SnTe and PbTe Thermoelectrics
2014 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 112, no 17, 175501- p.Article in journal (Refereed) Published
The anharmonic lattice dynamics of rock-salt thermoelectric compounds SnTe and PbTe are investigated with inelastic neutron scattering (INS) and first-principles calculations. The experiments show that, surprisingly, although SnTe is closer to the ferroelectric instability, phonon spectra in PbTe exhibit a more anharmonic character. This behavior is reproduced in first-principles calculations of the temperature-dependent phonon self-energy. Our simulations reveal how the nesting of phonon dispersions induces prominent features in the self-energy, which account for the measured INS spectra and their temperature dependence. We establish that the phase space for three-phonon scattering processes, combined with the proximity to the lattice instability, is the mechanism determining the complex spectrum of the transverse-optic ferroelectric mode.
Place, publisher, year, edition, pages
American Physical Society , 2014. Vol. 112, no 17, 175501- p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-107454DOI: 10.1103/PhysRevLett.112.175501ISI: 000335816700014OAI: oai:DiVA.org:liu-107454DiVA: diva2:724315