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Electron and orbital correlations in Ca_{2-x}Sr_{x}RuO_{4} probed by optical spectroscopy

J. S. Lee·Y. S. Lee·T. W. Noh·S. -J. Oh·Jaejun Yu·S. Nakatsuji·H. Fukazawa·Y. Maeno
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Abstract

The doping and temperature dependent optical conductivity spectra of the quasi-two-dimensional Ca_{2-x}Sr_xRuO_4 (0.0=<x=<2.0) system were investigated. In the Mott insulating state, two electron correlation-induced peaks were observed around 1.0 and 1.9 eV, which could be understood in terms of the 3-orbital Hubbard model. The low frequency peak showed a shift toward higher frequency as temperature was lowered, which indicated that electron-phonon interactions play an important role in the orbital arrangements. From the systematic analysis, it was suggested that the antiferro-orbital and the ferro-orbital ordering states could coexist.

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J. S. Lee, Y. S. Lee, T. W. Noh, S. -J. Oh, Jaejun Yu, S. Nakatsuji, H. Fukazawa, Y. Maeno. 2002-08-11. Electron and orbital correlations in Ca_{2-x}Sr_{x}RuO_{4} probed by optical spectroscopy. https://doi.org/10.1103/physrevlett.89.257402

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