Lattice dynamical origin of peak thermoelectric performance in AgPbmSbTe2+m observed by inelastic neutron scattering

Abstract

Phonon densities of states (DOS) for the high performing thermoelectric material, AgPbmSbTe2+m (LAST-m, m = 16, 18, and 20), were extracted from time-of-flight inelastic neutron scattering measurements. The phonon DOS of LAST-18 differs remarkably from LAST-16 and LAST-20 by exhibiting a dramatic broadening of its acoustic modes that increases on heating. This broadening coincides with a minimum in the thermal conductivity, a maximum in the electrical conductivity and Seebeck coefficient, and a related peak in thermoelectric performance. We argue that the anomalous broadening originates with scattering enhanced by modifications to Te-Ag(Sb) bonds caused by their resonant electronic states falling near the Fermi energy for m = 18.

arXiv comment13 pages, 2 figures

References in corpus (4)

• Reversible thermoelectric nanomaterials
• Resonant States in the Electronic Structure of the High Performance Thermoelectrics AgPb${}_{m}SbTe$_{2+m}$ ; The Role of Ag-Sb Microstructures
• First-Principles Theory of Competing Order Types, Phase Separation, and Phonon Scattering in Thermoelectric Pb-Sb-Ag-Te Alloys
• Impurity clustering and impurity-induced bands in PbTe-, SnTe-, and GeTe-based bulk thermoelectrics

Cited by in corpus (1)

• Phonon Density of States and Anharmonicity of UO2