2013/12/28 by C. W. Li, Chen Li, O. Hellman +15 · 4 citations
Engineering · Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #Anharmonicity #Condensed matter physics #Ferroelectricity #Inelastic neutron scattering #Inelastic scattering #Instability #Materials science #Neutron scattering #Optics #Phonon #Phonon scattering #Physics #Quantum mechanics #Scattering #Soft modes #Spectral line #Thermal Radiation and Cooling Technologies #Thermal properties of materials #Thermoelectric effect #Thermoelectric materials #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.112.175501
arxiv created 2013/12/28 · openalex publication_date 2014/04/30 · arxiv updated 2015/06/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.