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Temperature and pressure dependence of the Fe-specific phonon density of states in Ba ( Fe1-x Cox)2As2

Publication ,  Journal Article
Delaire, O; Lucas, MS; Dos Santos, AM; Subedi, A; Sefat, AS; McGuire, MA; Mauger, L; Muñoz, JA; Tulk, CA; Xiao, Y; Somayazulu, M; Zhao, JY ...
Published in: Physical Review B - Condensed Matter and Materials Physics
March 4, 2010

The 57Fe -specific phonon density of states (DOS) of Ba (Fe 1-x Cox)2 As2 single crystals (x=0.0,0.08) was measured at cryogenic temperatures and at high pressures with nuclear-resonant inelastic x-ray scattering. Measurements were conducted for two different orientations of the single crystals, yielding the orientation-projected 57Fe -phonon density of states for phonon polarizations in-plane and out-of-plane with respect to the basal plane of the crystal structure. In the tetragonal phase at 300 K, a clear stiffening was observed upon doping with Co. Increasing pressure to 4 GPa caused a marked increase of phonon frequencies, with the doped material still stiffer than the parent compound. Upon cooling, both the doped and undoped samples showed a stiffening and the parent compound exhibited a discontinuity across the magnetic and structural phase transitions. These findings are generally compatible with the changes in volume of the system upon doping, increasing pressure, or increasing temperature, but an extra softening of high-energy modes occurs with increasing temperature. First-principles computations of the phonon DOS were performed and showed an overall agreement with the experimental results, but underestimate the Grüneisen parameter. This discrepancy is explained in terms of a magnetic Grüneisen parameter, causing an extra phonon stiffening as magnetism is suppressed under pressure. © 2010 The American Physical Society.

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Published In

Physical Review B - Condensed Matter and Materials Physics

DOI

EISSN

1550-235X

ISSN

1098-0121

Publication Date

March 4, 2010

Volume

81

Issue

9

Related Subject Headings

  • Fluids & Plasmas
  • 09 Engineering
  • 03 Chemical Sciences
  • 02 Physical Sciences
 

Citation

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Delaire, O., Lucas, M. S., Dos Santos, A. M., Subedi, A., Sefat, A. S., McGuire, M. A., … Egami, T. (2010). Temperature and pressure dependence of the Fe-specific phonon density of states in Ba ( Fe1-x Cox)2As2. Physical Review B - Condensed Matter and Materials Physics, 81(9). https://doi.org/10.1103/PhysRevB.81.094504
Delaire, O., M. S. Lucas, A. M. Dos Santos, A. Subedi, A. S. Sefat, M. A. McGuire, L. Mauger, et al. “Temperature and pressure dependence of the Fe-specific phonon density of states in Ba ( Fe1-x Cox)2As2.” Physical Review B - Condensed Matter and Materials Physics 81, no. 9 (March 4, 2010). https://doi.org/10.1103/PhysRevB.81.094504.
Delaire O, Lucas MS, Dos Santos AM, Subedi A, Sefat AS, McGuire MA, et al. Temperature and pressure dependence of the Fe-specific phonon density of states in Ba ( Fe1-x Cox)2As2. Physical Review B - Condensed Matter and Materials Physics. 2010 Mar 4;81(9).
Delaire, O., et al. “Temperature and pressure dependence of the Fe-specific phonon density of states in Ba ( Fe1-x Cox)2As2.” Physical Review B - Condensed Matter and Materials Physics, vol. 81, no. 9, Mar. 2010. Scopus, doi:10.1103/PhysRevB.81.094504.
Delaire O, Lucas MS, Dos Santos AM, Subedi A, Sefat AS, McGuire MA, Mauger L, Muñoz JA, Tulk CA, Xiao Y, Somayazulu M, Zhao JY, Sturhahn W, Alp EE, Singh DJ, Sales BC, Mandrus D, Egami T. Temperature and pressure dependence of the Fe-specific phonon density of states in Ba ( Fe1-x Cox)2As2. Physical Review B - Condensed Matter and Materials Physics. 2010 Mar 4;81(9).

Published In

Physical Review B - Condensed Matter and Materials Physics

DOI

EISSN

1550-235X

ISSN

1098-0121

Publication Date

March 4, 2010

Volume

81

Issue

9

Related Subject Headings

  • Fluids & Plasmas
  • 09 Engineering
  • 03 Chemical Sciences
  • 02 Physical Sciences