Structural relationship between negative thermal expansion and quartic anharmonicity of cubic ScF3
- California Institute of Technology, Pasadena
- ORNL
Cubic scandium trifluoride (ScF{sub 3}) has a large negative thermal expansion over a wide range of temperatures. Inelastic neutron scattering experiments were performed to study the temperature dependence of the lattice dynamics of ScF{sub 3} from 7 to 750 K. The measured phonon densities of states show a large anharmonic contribution with a thermal stiffening of modes around 25 meV. Phonon calculations with first-principles methods identified the individual modes in the densities of states, and frozen phonon calculations showed that some of the modes with motions of F atoms transverse to their bond direction behave as quantum quartic oscillators. The quartic potential originates from harmonic interatomic forces in the DO{sub 9} structure of ScF{sub 3}, and accounts for phonon stiffening with the temperature and a significant part of the negative thermal expansion.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1032797
- Journal Information:
- Physical Review Letters, Vol. 107, Issue 19; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pronounced negative thermal expansion from a simple structure : Cubic ScF{sub 3}.
Phonon quarticity induced by changes in phonon-tracked hybridization during lattice expansion and its stabilization of rutile
Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANHARMONIC OSCILLATORS
ATOMS
CUBIC LATTICES
HARMONICS
INTERATOMIC FORCES
NEUTRON DIFFRACTION
OSCILLATORS
PHONONS
SCANDIUM FLUORIDES
INELASTIC SCATTERING
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMAL EXPANSION