Goldstone-Mode Phonon Dynamics in the Pyrochlore Cd2Re2O7

C. A. Kendziora; I. A. Sergienko; R. Jin; J. He; V. Keppens; B. C. Sales; D. Mandrus

doi:10.1103/PhysRevLett.95.125503

Goldstone-Mode Phonon Dynamics in the Pyrochlore Cd2Re2O7

Materials Science 2007-05-23 v2 Superconductivity

Authors: C. A. Kendziora , I. A. Sergienko , R. Jin , J. He , V. Keppens , B. C. Sales , D. Mandrus

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Abstract

We have measured the polarized Raman scattering spectra of Cd2Re2O7, the first superconducting pyrochlore, as a function of temperature. For temperatures below the cubic-to-tetragonal structural phase transition (SPT) at 200K, a peak with B1 symmetry develops at zero frequency with divergent intensity. We identify this peak as the first observation of the Goldstone phonon in a crystalline solid. The Goldstone phonon is a collective excitation that exists due to the breaking of the continuous symmetry with the SPT. Its emergence coincides with that of a Raman-active soft mode. The order parameter for both features derives from an unstable doubly-degenerate vibration (with Eu symmetry) of the O1 atoms which drives the SPT.

Keywords

phonon physics phonon modes and lattice dynamics raman spectroscopy

Cite

@article{arxiv.cond-mat/0503756,
  title  = {Goldstone-Mode Phonon Dynamics in the Pyrochlore Cd2Re2O7},
  author = {C. A. Kendziora and I. A. Sergienko and R. Jin and J. He and V. Keppens and B. C. Sales and D. Mandrus},
  journal= {arXiv preprint arXiv:cond-mat/0503756},
  year   = {2007}
}

Comments

4+ pages, 4 figures. Updated figures and text. Accepted to PRL

Goldstone-Mode Phonon Dynamics in the Pyrochlore Cd2Re2O7

Abstract

Keywords

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