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The infrared spectrum of Na_0.57CoO_2

S. Lupi·M. Ortolani·P. Calvani
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Abstract

The optical conductivity of single crystals of Na_xCoO_2 for $x$ = 0.57 is first reported between 295 and 30 K. In the far infrared, an "anomalous Drude" analysis leads to a carrier effective mass of 5 electron masses. That this high value is due to strong electron-phonon coupling is suggested by the Fano distortion of a phonon at 570 cm^-1. A peak at 8800 cm^-1 scales with the charge transfer band of several high-$T_c$ cuprates by simply replacing the in-plane Cu-O bond length with that for Co-O.

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S. Lupi, M. Ortolani, P. Calvani. 2003-12-19. The infrared spectrum of Na_0.57CoO_2. https://doi.org/10.1103/physrevb.69.180506

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