Insulator-metal transition driven by pressure and B-site disorder in double perovskite La 2CoMnO 6

Shuhui Lv, Xiaojuan Liu, Hongping Li, Lin Han, Zhongchang Wang, Jian Meng

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    14 Citations (Scopus)

    Abstract

    The ground state of double perovskite oxide La 2CoMnO 6 (LCMO) and how it is influenced by external pressure and antisite disorder are investigated systematically by firstprinciples calculations. We find, on the consideration of both the electron correlation and spin-orbital coupling effect, that the LCMO takes on insulating nature, yet is transformed to half metallicity once the external pressure is introduced. Such tuning is accompanied by a spin-state transition of Co 2+ from the high-spin state (t 2g 5e g 2) to low-spin state (t 2g 6e g 1) because of the enhancement of crystal-field splitting under pressure. Using mean-field approximation theory, Curie temperature of LCMO with Co 2+ being in low-spin state is predicted to be higher than that in high-spin state, which is attributed to the enhanced ferromagnetic double exchange interaction arising from the shrinkage of CoAO and MnAO bonds as well as to the increase in bond angle of CoAOAMn under pressure. We also find that antisite disorder in LCMO enables such transition from insulating to half-metallic state as well, which is associated with the spin-state transition of antisite Co from high to low state. It is proposed that the substitution of La 3+ for the rare-earth (RE) ions with smaller ionic radii could open up an avenue to induce a spin-state transition of Co, rendering thereby the RE 2CoMnO 6 a promising half-metallic material.

    Original languageEnglish
    Pages (from-to)1433-1439
    Number of pages7
    JournalJournal of Computational Chemistry
    Volume33
    Issue number16
    DOIs
    Publication statusPublished - 2012

    Keywords

    • Double perovskite
    • First-principles calculation
    • Insulator-metal transition
    • La CoMnO
    • Spin state

    ASJC Scopus subject areas

    • Chemistry(all)
    • Computational Mathematics

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