skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on March 27, 2019

Title: Crossover of thermal expansion from positive to negative by removing the excess fluorines in cubic ReO 3-type TiZrF 7-x

Here, we report the crossover of the coefficient of thermal expansion (CTE) from positive to negative by withdrawing the excess fluorines in ReO 3-type TiZrF 7-x (x = 0, 0.5 and 1) compounds. The average volumetric CTE between 300 K and 623 K changes from 8.07 ppm K -1 for x = 0, to 0.66 ppm K -1 for x = 0.5 and finally to -6.09 ppm K -1 for x = 1. After withdrawing the excess fluorines, the lattice expands and the edge-sharing polyhedra partially transform to corner-sharing ones, which enhances the transverse vibrations of fluorines and thus accounts for the crossover of CTE. Moreover, these compounds are narrow-gap semiconductors with the energy gap decreasing with x. NTE may also be achievable in other fluorine-excess cubic fluorides by removing the excess fluorines, which opens up a new avenue for exploring the NTE in fluorides.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [3] ; ORCiD logo [1] ;  [4] ;  [4] ;  [5] ;  [1] ;  [4] ;  [4] ;  [6]
  1. Chinese Academy of Sciences (CAS), Hefei (China). Key Lab. of Materials Physics and Inst. of Solid State Physics; Univ. of Science and Technology of China, Hefei (China)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
  3. Hefei Univ. of Technology (China). Lab. of Amorphous Materials and School of Materials Science and Engineering
  4. Chinese Academy of Sciences (CAS), Hefei (China). Key Lab. of Materials Physics and Inst. of Solid State Physics
  5. Chinese Academy of Sciences (CAS), Hefei (China). High Magnetic Field Lab.
  6. Chinese Academy of Sciences (CAS), Hefei (China). Key Lab. of Materials Physics, Inst. of Solid State Physics and High Magnetic Field Lab.
Publication Date:
Report Number(s):
BNL-207923-2018-JAAM
Journal ID: ISSN 2050-7526; JMCCCX
Grant/Contract Number:
SC0012704; QYZDB-SSW-SLH015; 51322105; U1632158
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Chemistry C
Additional Journal Information:
Journal Volume: 6; Journal Issue: 19; Journal ID: ISSN 2050-7526
Publisher:
Royal Society of Chemistry
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Natural Science Foundation of China (NNSFC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1463853
Alternate Identifier(s):
OSTI ID: 1434158