Nonuniform metallic state in manganites and cuprates

Abstract: Local lattice distortions suggesting nonuniform charge distributions were found to be a common feature of manganites and cuprates in the metallic state by neutron scattering studies. The atomic pair-density function (PDF) determined by pulsed neutron powder diffraction showed that in La_1-xSr_xMnO₃ doped holes form lattice polarons which persist even in the metallic state. In La_1.85Sr_0.15CuO₄ the energy width of the LO phonons around (π,0) determined by inelastic neutron scattering reflects magnetic satellites indicative of spin charge stripe formation. The implications of such nonuniform charge distribution for metal-insulator transition and superconductivity are discussed.