Journal Article

PreJuSER-5600

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Spin and orbital states in La1.5 Sr0.5 CoO4 studied by electronic structure calculations

Wu, H. ; Burnus, T.FZJ*

2009
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/11033  doi:10.1103/PhysRevB.80.081105

Abstract: Electronic structure of the layered perovskite La1.5Sr0.5CoO4 with a checkerboard Co2+/Co3+ charge order is studied, using the local-spin-density approximation plus Hubbard U calculations including also the spin-orbit coupling and multiplet effect. Our results show that the Co2+ ion is in a high spin state (HS, t(2g)(5)e(g)(2)) and Co3+ low spin state (LS, t(2g)(6)). Due to a small Co2+ t(2g) crystal field splitting, the spin-orbit interaction produces an orbital moment of 0.26 mu(B) and accounts for the observed easy in-plane magnetism. Moreover, we find that the Co3+ intermediate spin state (IS, t(2g)(5)e(g)(1)) has a multiplet splitting of several tenths of eV and the lowest-lying one is still higher than the LS ground state by 120 meV, and that the Co3+ HS state (t(2g)(4)e(g)(2)) is more unstable by 310 meV. Either the IS or HS Co3+ ions would give rise to a wrong magnetic order and anisotropy.

Keyword(s): J ; band structure (auto) ; density functional theory (auto) ; ground states (auto) ; Hubbard model (auto) ; lanthanum compounds (auto) ; magnetic anisotropy (auto) ; spin-orbit interactions (auto) ; strontium compounds (auto)

Note: This work was supported by the Deutsche Forschungsgemeinschaft through SFB 608.

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Contributing Institute(s):

1. Quanten-Theorie der Materialien (IFF-1)
2. Quanten-Theorie der Materialien (IAS-1)
3. Jülich-Aachen Research Alliance - Fundamentals of Future Information Technology (JARA-FIT)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)

Appears in the scientific report 2009

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