Infrared Properties of Na_xCoO₂ single crystals with x=0.5, 0.7, and 0.85

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Journal of Physics and Chemistry of Solids

DOI:https://doi.org/10.1016/j.jpcs.2005.10.092· OSTI ID:936015

Wu, D. ^[1]; Wang, N. L. ^[1]; Li, G ^[1]; Luo, J. L. ^[1]; Zheng, P. ^[1]; Chen, X. H. ^[2]; Wang, C. H. ^[2]; Luo, X. G. ^[2]; Jin, Rongying ^[3]; Mandrus, David ^[3]

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1. Chinese Academy of Sciences
2. University of Science and Technology, Beijing, China
3. ORNL

We present in-plane optical measurements on Na{sub x}CoO{sub 2} single crystals with x = 0.5, 0.7 and 0.85. We found that the spectral weight associated with the conducting carriers increases with decreasing Na contents. Anomalous charge dynamics for samples in the metallic regime was revealed. For x = 0.5 compound in the charge ordered state, the reflectance was strongly suppressed below 250 cm{sup -1}, resulting in a gap in conductivity spectrum. Similar but weak features have been found for x = 0.85 sample below 20 K. The optical data highlight the importance of charge ordering tendencies of Co ions in Na{sub x}CoO{sub 2}. In addition, a strong coupling effect of electron with a bosonic mode was also revealed.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 936015
• Journal Information: Journal of Physics and Chemistry of Solids, Journal Name: Journal of Physics and Chemistry of Solids Journal Issue: 1-3 Vol. 67; ISSN 0022-3697; ISSN JPCSAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT OXIDES
INFRARED SPECTRA
MONOCRYSTALS
ORDER PARAMETERS
REFLECTIVITY
SODIUM OXIDES