Lattice effect of strong electron correlation: implication for ferroelectricity and superconductivity.

Much theoretical work has been devoted to understanding the role of strong electron correlations in high-temperature superconductivity mainly through magnetic interactions, but the possible role of electron correlation in ferroelectricity of metal oxides has not received attention. Diagonalization of a simple many-body, tight-binding Hamiltonian shows that the electron-lattice interaction is dramatically enhanced in some cases by strong electron correlation because of deformation-induced charge transfer. This effect may be closely related to ferroelectricity and superconductivity in transition metal oxides.