Localized Symmetry Breaking for Tuning Thermal Expansion in ScF3 Nanoscale Frameworks

• DOI: 10.1021/jacs.8b00885
• Publication Date: 2018-03-20T22:03:19Z
• Authors: Lei Hu; Feiyu Qin; Andrea Sanson; Liang-Feng Huang; Zhao Pan; Qiang Li; Qiang Sun; Lu Wang; Fangmin Guo; Umut Aydemir; Yang Ren; Chengjun Sun; Jinxia Deng; Giuliana Aquilanti; James M. Rondinelli; Jun Chen; Xianran Xing
• Keywords: 01 natural sciences; 0104 chemical sciences

The local symmetry, beyond the averaged crystallographic structure, tends to bring unusual performances. Negative thermal expansion is a peculiar physical property of solids. Here, we report delicate design localized symmetry breaking achieve controllable in ScF3 nanoscale frameworks. Intriguingly, an isotropic zero concurrently engineered by breaking, with remarkably low coefficient about +4.0 × 10-8/K up 675 K. This mechanism investigated joint analysis atomic pair distribution function synchrotron X-ray total scattering and extended absorption fine structure spectra. A rhombohedral distortion presumably plays critical role stiffening frameworks concomitantly suppressing transverse vibrations fluorine atoms. scenario also theoretically corroborated extinction phonon modes negative Grüneisen parameters ScF3. present work opens untraditional chemical modification route symmetries materials.