All-Scale Hierarchical Structure Contributing to Ultralow Thermal Conductivity of Zintl Phase CaAg_0.2Zn_0.4Sb.

ABSTRACT: TiNiSi-type Zintl phase CaAgSb can transform into LiGaGe-type Zintl phase CaAg _x Zn_{(1- x )/2}Sb when some of the Ag atoms are substituted by Zn atoms, leading to an ultralow thermal conductivity of ≈0.4 W m^-1 K^-1 in the whole measured temperature range of CaAg_0.2Zn_0.4Sb. The microstructure is then investigated by spherical aberration-corrected electron microscopy on an atomic scale, which reveals an all-scale hierarchical structure that can scatter the phonons in a wide frequency range. There exist a large quantity of CaAgSb nanometer precipitates as well as quite a lot of edge dislocations close to these nanometer precipitates, thus releasing the stress caused by the mismatch between the p

SUBMITTER: Chen J 

PROVIDER: S-EPMC8188219 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature