Publication: Switch of thermal expansions triggered by itinerant electrons in isostructural metal trifluorides
Program
KU-Authors
KU Authors
Co-Authors
Qin, Feiyu
Wang, Xiaoying
Hu, Lei
Jia, Ning
Gao, Zhibin
Chen, Jun
Ding, Xiangdong
Sun, Jun
Advisor
Publication Date
2022
Language
English
Type
Journal Article
Journal Title
Journal ISSN
Volume Title
Abstract
Manageable thermal expansion (MTE) of metal trifluorides can be achieved by introducing local structure distortion (LSD) in the negative thermal expansion ScF3. However, an open issue is why isostructural TiF3, free of LSD, exhibits positive thermal expansion. Herein, a combined analysis of synchrotron X-ray diffraction, X-ray pair distribution function, and rigorous first-principles calculations was performed to reveal the important role of itinerant electrons in mediating soft phonons and lattice dynamics. Metallic TiF3 demonstrates itinerant electrons and a suppressed Gru''neisen parameter gamma -20, while insulating ScF3 absence of itinerant electrons has a considerable gamma -120. With increasing electron doping concentrations in ScF3, soft phonons become hardened and the gamma is repressed significantly, identical to TiF3. The presented results update the thermal expansion transition mechanism in framework structure analogues and provide a practical approach to obtaining MTE without inducing sizable structure distortion.
Description
Source:
Inorganic Chemistry
Publisher:
American Chemical Society (ACS)
Keywords:
Subject
Chemistry, Inorganic, Nuclear