Hidden Charge Order in an Iron Oxide Square-Lattice Compound

Jung-Hwa Kim, Darren C. Peets, Manfred Reehuis +14

Since the discovery of charge disproportionation in the FeO${}_2$ square-lattice compound Sr${}_3$Fe${}_2$O${}_7$ by Mössbauer spectroscopy more than fifty years ago, the spatial ordering…