Spin polaron theory for the photoemission spectra of layered cobaltates

Abstract

Recently, strong reduction of the quasiparticle peaks and pronounced incoherent structures have been observed in the photoemission spectra of layered cobaltates. Surprisingly, these many-body effects are found to increase near the band insulator regime. We explain these unexpected observations in terms of a novel spin-polaron model for CoO_2 planes which is based on a fact of the spin-state quasidegeneracy of Co^{3+} ions in oxides. Scattering of the photoholes on spin-state fluctuations suppresses their coherent motion. The observed ``peak-dip-hump'' type lineshapes are well reproduced by the theory.

4 pages, 4 figures

References in corpus (9)

• The spin state transition in LaCoO${}_3$; revising a revision
• Electron correlation and Fermi surface topology of Na${}_x$CoO${}_2$
• Evidence of a single nonmagnetic Co3+ state in the Na1CoO2 cobaltate
• Complete d-Band Dispersion and the Mobile Fermion Scale in NaxCoO2
• Electronic Correlations in CoO2, the Parent Compound of Triangular Cobaltates
• Apparent electron-phonon interaction in strongly correlated systems
• Interplay between magnetic properties and thermoelectricity in misfit and Na cobaltates
• Magnetic properties of spin-orbital polarons in lightly doped cobaltates
• Direct observation of strong correlations near the band insulator regime of Bi misfit cobaltates

Cited by in corpus (4)

• Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration
• Origin of the electron disproportionation in the metallic sodium cobaltates
• Superconductivity in the spin-state crossover materials: Nickelates with planar-coordinated low-spin Ni${}^{2+}$ ions
• Magnetic polarons due to spin-length fluctuations in ${\mathbf{d}}^4$ spin-orbit Mott systems