Charge order and phonon renormalizations: Possible implications for cobaltates

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 $H_{2}O$ content the system is pushed closer to CO, the mentioned phonon modes should show softening and broadening.

4 pages, 4 figures, accepted for publication in Phys. Rev. B

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Cited by in corpus (2)

• Charge disproportionation and collinear magnetic order in the frustrated triangular antiferromagnet AgNiO2
• Electron-phonon interaction in the lamellar cobaltate Na${}_x$CoO${}_2$