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Inelastic Neutron Scattering and Density Functional Theory- Molecular Dynamics Study of Si Dynamics in Ti3SiC2

Kearley, Gordon J.; Gray, Veronica; Riley, Daniel P.; Kirstein, Oliver LU ; Kutteh, Ramzi and Kisi, Erich H. (2014) In Journal of the American Ceramic Society 97(3). p.916-922
Abstract
Observed differences between measured and calculated elastic constants for Ti3SiC2 are investigated using Density Functional Theory and Inelastic Neutron Scattering. The agreement between the calculated lattice dynamics and the dynamics measured by inelastic neutron scattering is considered good except at energies below similar to 20meV where discrepancies suggest anharmonic potentials. This suggestion is confirmed by Density Functional TheoryMolecular Dynamics simulation which shows multiple site occupancy of the Si atoms within the basal plane at finite temperature and produces a calculated inelastic spectrum in better agreement with the measured spectrum in the low-energy region. The highly anharmonic potential energy surface of the Si... (More)
Observed differences between measured and calculated elastic constants for Ti3SiC2 are investigated using Density Functional Theory and Inelastic Neutron Scattering. The agreement between the calculated lattice dynamics and the dynamics measured by inelastic neutron scattering is considered good except at energies below similar to 20meV where discrepancies suggest anharmonic potentials. This suggestion is confirmed by Density Functional TheoryMolecular Dynamics simulation which shows multiple site occupancy of the Si atoms within the basal plane at finite temperature and produces a calculated inelastic spectrum in better agreement with the measured spectrum in the low-energy region. The highly anharmonic potential energy surface of the Si atoms offers an explanation for the failure of elastic constants, calculated based on the harmonic approximation, to agree with initial experimental measurements. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the American Ceramic Society
volume
97
issue
3
pages
916 - 922
publisher
Wiley-Blackwell
external identifiers
  • wos:000332195700039
  • scopus:84897638113
ISSN
1551-2916
DOI
10.1111/jace.12725
language
English
LU publication?
yes
id
d962e6fd-0948-4a3d-96f8-f0ec35e33463 (old id 4414321)
date added to LUP
2014-04-30 08:02:53
date last changed
2017-02-26 03:18:05
@article{d962e6fd-0948-4a3d-96f8-f0ec35e33463,
  abstract     = {Observed differences between measured and calculated elastic constants for Ti3SiC2 are investigated using Density Functional Theory and Inelastic Neutron Scattering. The agreement between the calculated lattice dynamics and the dynamics measured by inelastic neutron scattering is considered good except at energies below similar to 20meV where discrepancies suggest anharmonic potentials. This suggestion is confirmed by Density Functional TheoryMolecular Dynamics simulation which shows multiple site occupancy of the Si atoms within the basal plane at finite temperature and produces a calculated inelastic spectrum in better agreement with the measured spectrum in the low-energy region. The highly anharmonic potential energy surface of the Si atoms offers an explanation for the failure of elastic constants, calculated based on the harmonic approximation, to agree with initial experimental measurements.},
  author       = {Kearley, Gordon J. and Gray, Veronica and Riley, Daniel P. and Kirstein, Oliver and Kutteh, Ramzi and Kisi, Erich H.},
  issn         = {1551-2916},
  language     = {eng},
  number       = {3},
  pages        = {916--922},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of the American Ceramic Society},
  title        = {Inelastic Neutron Scattering and Density Functional Theory- Molecular Dynamics Study of Si Dynamics in Ti3SiC2},
  url          = {http://dx.doi.org/10.1111/jace.12725},
  volume       = {97},
  year         = {2014},
}