Charge order and phonon renormalizations: Possible implications for cobaltates

M. BEJAS; A. GRECO; A. FOUSSATS

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

The American Physical Society

Año: 2007 vol. 75 p. 331011 - 331014

0163-1829

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 H2O content the system is pushed closer to CO, the mentioned phonon modes should show softening and broadening.