Charge ordering

Charge ordering (CO) is a (first- or second-order) phase transition occurring mostly in strongly correlated materials such as transition metal oxides or organic conductors. Due to the strong interaction between electrons, charges are localized on different sites leading to a disproportionation and an ordered superlattice. It appears in different patterns ranging from vertical to horizontal stripes to a checkerboard–like pattern [1][2] , and it is not limited to the two-dimensional case. The charge order transition is accompanied by symmetry breaking and may lead to ferroelectricity. It is often found in close proximity to superconductivity and colossal magnetoresistance.

Charge order patterns


This long range order phenomena was first discovered in magnetite (Fe3O4) by Verwey in 1939.[3][4] He observed an increase of the electrical resistivity by two orders of magnitude at TCO=120K, suggesting a phase transition which is now well known as the Verwey transition. He was the first to propose the idea of an ordering process in this context. The charge ordered structure of magnetite was solved in 2011 by a group led by Paul Attfield with the results published in Nature.[5] Periodic lattice distortions associated with charge order were later mapped in the manganite lattice to reveal striped domains containing topological disorder.[6]

  1. ^ Wise, W.D.; et al. (2008). "Charge-density-wave origin of cuprate checkerboard visualized by scanning tunnelling microscopy". PNAS. 4 (9): 696–699. arXiv:0806.0203. Bibcode:2008NatPh...4..696W. doi:10.1038/nphys1021. S2CID 14314484.
  2. ^ Savitzky, B.; et al. (2017). "Bending and breaking of stripes in a charge ordered manganite". Nature Communications. 8 (1): 1883. arXiv:1707.00221. Bibcode:2017NatCo...8.1883S. doi:10.1038/s41467-017-02156-1. PMC 5709367. PMID 29192204.
  3. ^ Verwey, E.J.W. (1939). "Electronic conduction of magnetite (Fe3O4) and its transition point at low temperatures". Nature. 144 (3642): 327–328. Bibcode:1939Natur.144..327V. doi:10.1038/144327b0. S2CID 41925681.
  4. ^ Verwey, E.J.W.; Haayman, P.W. (1941). "Electronic conductivity and transition point of magnetite (Fe3O4)". Physica. 8 (9): 979–987. Bibcode:1941Phy.....8..979V. doi:10.1016/S0031-8914(41)80005-6.
  5. ^ Senn, M. S.; Wright, J. P.; Attfield, J. P. (2011). "Charge order and three-site distortions in the Verwey structure of magnetite" (PDF). Nature. 481 (7380): 173–6. Bibcode:2012Natur.481..173S. doi:10.1038/nature10704. hdl:20.500.11820/1b3bb558-52d5-419f-9944-ab917dc95f5e. PMID 22190035. S2CID 4425300.
  6. ^ El Baggari, I.; et al. (2017). "Nature and evolution of incommensurate charge order in manganites visualized with cryogenic scanning transmission electron microscopy". PNAS. 115 (7): 1–6. arXiv:1708.08871. Bibcode:2018PNAS..115.1445E. doi:10.1073/pnas.1714901115. PMC 5816166. PMID 29382750.