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Charge order and phonon renormalizations: Possible implications for cobaltates

M. Bejas·A. Greco·A. Foussats
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Abstract

Several experimental and theoretical studies in cobaltates suggest the proximity of the system to charge ordering (CO). We show, qualitatively, in the frame of a $t-V$ model coupled to phonons that optical phonon modes at the $K$ and $M$ points of the Brillouin zone, which involves only $O$-ions displacement around a $Co$-ion, are good candidates to display anomalies due to the CO proximity. If by increasing of $H_2O$ content the system is pushed closer to CO, the mentioned phonon modes should show softening and broadening.

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M. Bejas, A. Greco, A. Foussats. 2006-12-14. Charge order and phonon renormalizations: Possible implications for cobaltates. https://doi.org/10.1103/physrevb.75.033101

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