Direct atomic-scale observation of the Ag+ diffusion structure in the quasi-2D "liquid-like" state of superionic thermoelectric AgCrSe2

被引：22

作者：

Xie, Lin ^{[1
]}

Wu, Di ^{[1
]}

Yang, Hongliang ^{[1
]}

Yu, Yong ^{[1
]}

Wang, Yifan ^{[1
]}

He, Jiaqing ^{[1
]}

机构：

[1] Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China

来源：

JOURNAL OF MATERIALS CHEMISTRY C | 2019年 / 7卷 / 30期

基金：

中国国家自然科学基金;

关键词：

ORDER-DISORDER TRANSITION; TOTAL-ENERGY CALCULATIONS; CONDUCTIVITY; PERFORMANCE;

D O I：

10.1039/c9tc03235e

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

"Phonon-Liquid Electron-Crystal (PLEC)" materials are attractive thermoelectric systems due to their emergent liquid-like behavior, which potentially leads to ultralow lattice thermal conductivity and moderate thermoelectric performance at high temperature. In this paper, the "liquid-like" state's atomic structure of the quasi-2D PLEC AgCrSe2 is directly studied by in situ scanning transmission electron microscopy and ab initio molecular dynamics. It is revealed by experiments that the diffusing Ag atoms in the liquid-like state prefer to occupy lattice sites as in a disordered solid, a feature very distinct from that of real liquids, and theoretical calculations predict that the characteristic time for Ag+ diffusion is too slow to disrupt vibrations. A simple slow diffusion model is proposed to elucidate the "liquid-like" behavior, and the ultralow lattice thermal conductivity can be explained within the framework of disorder solids.

引用

页码：9263 / 9269

页数：7