Structural relationship between negative thermal expansion and quartic anharmonicity of cubic ScF3

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.107.195504· OSTI ID:1032797

Li, Chen W. ^[1]; Tang, Xiaoli ^[1]; Munoz, Jorge A. ^[1]; Keith, J. Brian ^[1]; Tracy, Sally J. ^[1]; Abernathy, Douglas L ^[2]; Fultz, B. ^[1]

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1. California Institute of Technology, Pasadena
2. 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 Laboratory (ORNL); Spallation Neutron Source
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1032797
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 19 Vol. 107; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANHARMONIC OSCILLATORS
ATOMS
CUBIC LATTICES
HARMONICS
INELASTIC SCATTERING
INTERATOMIC FORCES
NEUTRON DIFFRACTION
OSCILLATORS
PHONONS
SCANDIUM FLUORIDES
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