Intrinsic Ultralow Lattice Thermal Conductivity in the Full-Heusler Compound Ba2AgSb

• DOI: 10.1103/physrevapplied.17.034023
• Publication Date: 2022-03-08T17:35:26Z
• Authors: Shao-Fei Wang; Zhi-Gang Zhang; Bao-Tian Wang; Jun-Rong Zhang; Fang-Wei Wang
• Keywords: Phonon scattering

Full-Heusler thermoelectric materials have intrinsically low lattice thermal conductivity. Our first-principles calculations show that ${\mathrm{Ba}}_{2}\mathrm{Ag}\mathrm{Sb}$ is a semiconductor with an indirect band gap of 0.49 eV. The electronic degeneracy and pockets near the Fermi level facilitate electron transport. short phonon relaxation time, small group velocity (1.89 km ${\mathrm{s}}^{\ensuremath{-}1}$), large scattering space reflect intense phonon-phonon scattering. Gr\"uneisen parameter (1.44) accounts for strong anharmonicity, thus conductivity $0.5\phantom{\rule{0.1em}{0ex}}\mathrm{W}\phantom{\rule{0.1em}{0ex}}{\mathrm{m}}^{\ensuremath{-}1}\phantom{\rule{0.1em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$ at 800 K. isotropic figure merit maximum value 4.7 750 K comparable to reported materials. distribution momentum uncovers important role $\mathrm{Ag}$ in resisting analysis symmetry-based routes reveals significance symmetry on crystal structure can be used regulate chemical elements build high-performance provide effective way design materials, stimulating study full-Heusler