Electron-lattice interactions in nickel-oxide perovskites

摘要

The AMO_3 perovskites containing a first-row transition-metal atom M allow study of the cross-over from localized to itinerant electronic behavior in a single-valent MO_3 array dominated by (180 deg - PHI ) M-O-M interactions. The LnNiO_3 perovskites with Ln a lanthanide have one electron per low-spin Ni(III) in a narrow sigma ~* band that approaches cross-over from the itinerant-electron side. Transport measurements are reported that add to the mounting evidence for a heterogeneous electronic transition in the perovskites rather than the homogeneous transition assumed in conventional treatments of the Mott-Hubbard transition.