Electronic structure and lattice dynamics of LixCoO2 single crystals

H. L. Liu, T. Y. Ou-Yang, H. H. Tsai, P. A. Lin, H. T. Jeng, G. J. Shu, F. C. Chou

研究成果: 雜誌貢獻期刊論文同行評審

11 引文 斯高帕斯(Scopus)

摘要

Spectroscopic ellipsometry and Raman scattering measurements of single-crystal LixCoO2 (x = 0.33, 0.43, 0.50, 0.53, 0.72, and 0.87) are reported. The room temperature optical absorption spectra for x values in the range of 0.33-0.72 exhibit three bands near 1.60, 3.35, and 5.20 eV. On the basis of first-principles calculations, the observed optical excitations were appropriately assigned. The charge-transfer absorption bands shift to higher energies in Li0.87CoO2 because of symmetry-breaking-induced distortions of the hybridized Co-O orbitals with shifted oxygen 2p states. Furthermore, two Raman-active phonon modes, which display Eg and A1g symmetry, are sensitive to lithium doping. Upon cooling across 200 K, which is the antiferromagnetic phase transition temperature of Li0.50CoO2, large splitting of the Eg mode and a discontinuous change in the frequency of the A1g mode were observed. These results highlight the importance of spin-phonon coupling in Li0.50CoO2.

原文英語
文章編號103004
期刊New Journal of Physics
17
發行號10
DOIs
出版狀態已發佈 - 2015 九月 30

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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