Excitonic dispersion of the intermediate-spin state in LaCoO${}_3$ revealed by resonant inelastic X-ray scattering

Abstract

More than 50 years ago the electron-hole attraction was proposed to drive narrow gap semiconductors or semimetals to a new phase, the excitonic insulator. The experimental proof of its existence in bulk materials remains elusive. In strongly correlated insulators, the proximity of the excitonic insulator phase is reflected by the presence of dispersive electron-hole excitations with a small gap above a singlet ground state. Recently, such an excitation spectrum was proposed to be realized in perovskite oxide LaCoO${}_3$. In this Letter we use Co $L_3$-edge resonant inelastic X-ray scattering to put this proposal to experimental test.

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Cited by in corpus (12)

• LDA+DMFT approach to resonant inelastic x-ray scattering in correlated materials
• Collective Modes in Excitonic Magnets: Dynamical Mean-Field Study
• A New Era of Excitonic Insulators
• Damping of spinful excitons in LaCoO${}_3$ by thermal fluctuations: Theory and experiment
• Circular Dichroism in Resonant Inelastic X-ray Scattering: Probing Altermagnetic Domains in MnTe
• Ferromagnetism of LaCoO${}_3$ films
• FFLO Superconductivity Mediated by Excitonic Fluctuation in Semimetallic Ta${}_2$NiSe${}_5$
• Quantum paramagnet near spin-state transition
• Pressure-induced spin-state ordering in Sr${}_2$CoO${}_3$F
• Evolution of valence-specific spin states and local distortions in La${}_{2-x}$Sr${}_x$CoO${}_4$
• Optical signatures of strain-induced ferromagnetism in LaCoO${}_3$ thin film
• Long-lived relaxation channel and exciton-phonon coupling in Ta2NiSe5 via non-degenerate pump-probe spectroscopy