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Charge localization and phonon spectra in hole doped La2NiO4

R. J. McQueeney·A. R. Bishop·Ya-Sha Yi·Z. G. Yu
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Abstract

The in-plane oxygen vibrations in La2NiO4 are investigated for several hole-doping concentrations both theoretically and experimentally via inelastic neutron scattering. Using an inhomogeneous Hartree-Fock plus RPA numerical method in a two-dimensional Peierls-Hubbard model, it is found that the doping induces stripe ordering of localized charges, and that the strong electron-lattice coupling causes the in-plane oxygen modes to split into two subbands. This result agrees with the phonon band splitting observed by inelastic neutron scattering in La2-xSrxNiO4. Predictions of strong electron-lattice coupling in La2NiO4, the proximity of both oxygen-centered and nickel-centered charge ordering, and the relation between charged stripe ordering and the splitting of the in-plane phonon band upon doping are emphasized.

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R. J. McQueeney, A. R. Bishop, Ya-Sha Yi, Z. G. Yu. 2000-02-07. Charge localization and phonon spectra in hole doped La2NiO4. https://doi.org/10.1088/0953-8984%2F12%2F21%2F102

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