Orbital Degeneracy Removed by Charge Order in Triangular Antiferromagnet
- 11 October 2007
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 99 (15), 157204
- https://doi.org/10.1103/physrevlett.99.157204
Abstract
We report a high-resolution neutron diffraction study on the orbitally degenerate spin- hexagonal metallic antiferromagnet . A structural transition to a tripled unit cell with expanded and contracted octahedra indicates charge order on the Ni triangular lattice. This suggests charge order as a possible mechanism of lifting the orbital degeneracy in the presence of charge fluctuations, as an alternative to the more usual Jahn-Teller distortions. A novel magnetic ground state is observed at low temperatures with the electron-rich Ni sites arranged in alternating ferromagnetic rows on a triangular lattice, surrounded by a honeycomb network of nonmagnetic and metallic Ni ions. We also report first-principles band-structure calculations that explain microscopically the origin of these phenomena.
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This publication has 14 references indexed in Scilit:
- Formation of an unconventional Ag valence state inPhysical Review B, 2007
- Charge Ordering as Alternative to Jahn-Teller DistortionPhysical Review Letters, 2007
- Valence-skipping compounds as positive-U electronic systemsPhysical Review B, 2006
- Spin-triangular lattice with orbital degeneracy in a metallic oxidePhysical Review B, 2006
- Eine neue, hexagonale Modifikation von AgNiO2Zeitschrift für anorganische und allgemeine Chemie, 2005
- Electronic Frustration on a Triangular LatticeScience, 2004
- Study of the ferrodistorsive orbital ordering in NaNiO2 by neutron diffraction and submillimeter wave ESRZeitschrift für Physik B Condensed Matter, 2000
- Charge Disproportionation inPerovskites: Simultaneous Metal-Insulator and Structural Transition inPhysical Review Letters, 1999
- Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis setPhysical Review B, 1996
- Notiz zur Kenntnis der Oxocobaltate des NatriumsZeitschrift für anorganische und allgemeine Chemie, 1974