Direct observation of strong correlations near the band insulator regime of Bi misfit cobaltates

Abstract

We present the first angle-resolved photoemission (ARPES) measurement of Fermi Surface in the "misfit" cobaltate [Bi2Ba2O4].[CoO2]~2. This compound contains the same triangular Co planes as Na cobaltates, but in a different 3D environment. Our data establish the similarity of their electronic structure. We propose that the peculiar lineshape of all cobaltates is of the "peak-dip-hump" type, due to strong many-body effects. We detect a progressive transfer of spectral weight from the quasiparticle feature near Ef to a broad hump in misfit phases where Ba is replaced by Sr or Ca. This indicates stronger many-body interactions in proximity of the band insulator regime, which we attribute to the presence of unusual magnetic excitations.

arXiv comment4 pages, 4 figures

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Cited by in corpus (12)

• Interplay between magnetic properties and thermoelectricity in misfit and Na cobaltates
• The origin of strong correlations and superconductivity in Na${}_x$CoO${}_2$
• Experimental study of the incoherent spectral weight in the photoemission spectra of the misfit cobaltate [Bi2Ba2O4][CoO2]2
• Spin polaron theory for the photoemission spectra of layered cobaltates
• Considerable non-local electronic correlations in strongly doped Na${}_x$CoO${}_2$
• Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration
• Novel electronic structure induced by a highly strained oxide interface with incommensurate crystal fields
• New electronic orderings observed in cobaltates under the influence of misfit periodicities
• Theory of carrier concentration-dependent electronic behavior in layered cobaltates
• Is there a common theme behind the correlated-electron superconductivity in organic charge-transfer solids, cobaltates, spinels and fullerides?
• One-particle spectral properties of the t-J-$V$ model on the triangular lattice near charge order
• Similarities in electronic properties of organic charge-transfer solids and layered cobaltates