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Orbital-selective Mott-insulator transition in Ca 2 - x Sr x RuO 4

  • V.I. Anisimov
  • I.A. Nekrasov
  • D.E. Kondakov
  • T.M. Rice
  • M. Sigrist
Article

Abstract:

The electronic structures of the metallic and insulating phases of the alloy series Ca2-xSrxRuO4 (0 ≤x ≤ 2) are calculated using LDA, LDA+U and Dynamical Mean-Field Approximation methods. In the end members the groundstate respectively is an orbitally non-degenerate antiferromagnetic insulator (x = 0) and a good metal (x = 2). For x > 0.5 the observed Curie-Weiss paramagnetic metallic state which possesses a local moment with the unexpected spin S = 1/2, is explained by the coexistence of localized and itinerant Ru-4d-orbitals. For 0.2 < x < 0.5 we propose a state with partial orbital and spin ordering. An effective model for the localized orbital and spin degrees of freedom is discussed. The metal-insulator transition at x = 0.2 is attributed to a switch in the orbital occupation associated with a structural change of the crystal.

PACS. 75.30.-m Intrinsic properties of magnetically ordered materials – 75.50.-y Studies of specific magnetic materials 

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Copyright information

© EDP Sciences, Springer-Verlag 2002

Authors and Affiliations

  • V.I. Anisimov
    • 1
  • I.A. Nekrasov
    • 1
  • D.E. Kondakov
    • 1
  • T.M. Rice
    • 2
  • M. Sigrist
    • 2
  1. 1.Russian Academy of Sciences-Ural DivisionInstitute of Metal PhysicsRussia
  2. 2.Theoretische PhysikZürichSwitzerland

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