Role of orbitals in manganese oxides-ordering and fluctuation

R. Maezono, S. Murakami, N. Nagaosa, S. Ishihara, M. Yamanaka, H. C. Lee

Research output: Contribution to journalConference article

Abstract

We study the manganese oxides from the viewpoint of the strongly correlated doped Mott insulator. The magnetic ordering and the charge transport are governed by the orbital degrees of freedom, and their dimensionality is controlled by the anisotropic transfer integrals between the eg-orbitals. As x increases, the magnetic structure is predicted to change as A→F→A→C→G (F, ferromagnet; A, layered antiferromagnet; C, rod-type antiferromagnet; G, usual antiferromagnet), in agreement with experiments. Especially the orbital is aligned as dx2-y2 in the metallic A state, which explains the quasi 2D transport and no canting of the spin observed experimentally. Next we discuss the ferromagnetic state without the orbital ordering due to the quantum fluctuation. Here the interplay between the electron repulsion U and the Jahn-Teller electron-phonon interaction ELR is studied with a large d model. In addition to this strong correlation, we propose that the dynamical phase separation could explain the specific heat as well as the various anomalous physical properties, e.g. resistivity, photo-emission, etc.

Original languageEnglish
Pages (from-to)171-176
Number of pages6
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Volume63
Issue number1-2
DOIs
Publication statusPublished - 1999 Aug 16
EventProceedings of the 1998 7th NEC Symposium on Fundamental Approaches to New Material Phases: Phase Control in Spin-Charge-Orbital Complex Systems - Nasu, Japan
Duration: 1998 Oct 111998 Oct 15

Keywords

  • Manganese oxides
  • Mott insulator
  • Orbitals

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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