Anomalous electronic raman scattering in NaxCoO2. yH2O

Authors

P Lemmens, Max-Planck-Institute For Solid State Research
K. Y. Choi, Tohoku University
E Sherman, University of Toronto
Dapeng Chen, Max-Planck-Institute For Solid State ResearchFollow
C T Lin, Max-Planck-Institute For Solid State ResearchFollow
F. C. Chou, Center for Materials Science and Engineering, USA
B Keimer, Max Planck Institute For Solid State Research

RIS ID

41051

Publication Details

Lemmens, P., Choi, K., Sherman, E., Chen, D. P., Lin, C., Chou, F. & Keimer, B. (2006). Anomalous electronic raman scattering in NaxCoO2. yH2O. Physical Review Letters, 96 (16), 167204-1-167204-4.

Abstract

Raman scattering experiments on NaxCoO2·yH2O single crystals show a broad electronic continuum with a pronounced peak around 100  cm-1 and a cutoff at approximately 560  cm-1 over a wide range of doping levels. The electronic Raman spectra in superconducting and nonsuperconducting samples are similar at room temperature, but evolve in markedly different ways with decreasing temperature. For superconducting samples, the low-energy spectral weight is depleted upon cooling below T*∼150  K, indicating the opening of a pseudogap that is not present in nonsuperconducting materials. Weak additional phonon modes observed below T* suggest that the pseudogap is associated with charge ordering.