title: Possible Kondo physics near a metal-insulator crossover in the a-site ordered perovskite CaCu3Ir4O12.
abstract: The A-site ordered perovskite (AA(3)')B(4)O(12) can accommodate transition metals on both A' and B sites in the crystal structure. Because of this structural feature, it is possible to have narrow-band electrons interacting with broadband electrons from different sublattices. Here we report a new A-site ordered perovskite (CaCu(3))Ir(4)O(12) synthesized under high pressure. The coupling between localized spins on Cu(2+) and itinerant electrons from the Ir-O sublattice makes Kondo-like physics take place at a temperature as high as 80 K. Results from the local density approximation calculation have confirmed the relevant band structure. The magnetization anomaly found at 80 K can be well rationalized by the two-fluid model.
authors.affiliation: Materials Science and Engineering Program and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA and Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan and Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: J-G
authors.initials: JG
authors.lastname: Cheng
authors.forename: J-S
authors.initials: JS
authors.lastname: Zhou
authors.forename: Y-F
authors.initials: YF
authors.lastname: Yang
authors.forename: H D
authors.initials: HD
authors.lastname: Zhou
authors.forename: K
authors.initials: K
authors.lastname: Matsubayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Uwatoko
authors.forename: A
authors.initials: A
authors.lastname: MacDonald
authors.forename: J B
authors.initials: JB
authors.lastname: Goodenough