Observation of gapped quasiparticles in sodium charge-ordered Na1/2CoO2

Y. Xia, D. Qian, D. Hsieh, L. Wray, L. Viciu, R. J. Cava, M. Z. Hasan

    Research output: Contribution to journalArticlepeer-review


    Using high-resolution photoemission spectroscopy (ARPES), we present a systematic study of the insulating cobaltates. A single-particle gap opening suggests that due to the material's unique topology an anisotropic particle-hole instability is present. Unlike conventional density waves, charge stripes or band insulators, the onset of the gap depends on the quasiparticle's quantum coherence which occurs well below the symmetry-breaking temperature of the crystal. Results are found to be in good agreement with bulk resistivity, specific heat and optical measurements.

    Original languageEnglish (US)
    Pages (from-to)1007-1009
    Number of pages3
    JournalPhysica B: Condensed Matter
    Issue number5-9
    StatePublished - Apr 1 2008


    • Frustrated systems
    • Metal-insulator transition
    • Mott insulator
    • Sodium cobaltate
    • Triangular lattice

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Electrical and Electronic Engineering


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