Elliptical hole pockets in the Fermi surfaces of unhydrated and hydrated sodium cobalt oxides

Abstract

The surprise discovery of superconductivity below 5K in sodium cobalt oxides when hydrated with water has caught the attention of experimentalists and theorists alike. Most explanations for its occurence have focused heavily on the properties of some small elliptically shaped pockets predicted to be the electronically dominant Fermi surface sheet, but direct attempts to look for them have instead cast serious doubts over their existence. Here we present evidence that these pockets do indeed exist, based on bulk measurements of the electron momentum distribution in unhydrated and hydrated sodium cobalt oxides using the technique of x-ray Compton scattering.

References in corpus (17)

• Fermi surface and quasiparticle dynamics of Na(x)CoO2 {x=0.7} investigated by Angle-Resolved Photoemission Spectroscopy
• Fermi surface evolution and Luttinger theorem in Na${}_x$CoO${}_2$: a systematic photoemission study
• ARPES on Na${}_{0.6}$CoO${}_2$: Fermi surface, extended flat dispersion, and unusual band splitting
• Crystal Structure and Elementary Properties of NaxCoO2 (x = 0.32, 0.5, 0.6, 0.75, and 0.92) in the Three-Layer NaCoO2 Family
• Ferromagnetic fluctuation and possible triplet superconductivity in Na_xCoO_2*yH_2O: Fluctuation-exchange study of multi-orbital Hubbard model
• Electron correlation and Fermi surface topology of Na${}_x$CoO${}_2$
• Low-lying quasiparticle states and hidden collective charge instabilities in parent cobaltate superconductors (NaxCoO2)
• The Fermi surface of Na${}_x$CoO${}_2$
• Quasiparticle coherence and the nature of the metal-insulator phase transition in Na${}_x$CoO${}_2$
• Observation of a strongly nested Fermi surface in the shape-memory alloy Ni[0.62]Al[0.38]
• Destruction of the small Fermi surfaces in Na${}_x$CoO${}_2$ by Na disorder
• Ferromagnetic and triplet-pairing instabilities controlled by the trigonal distortion of the CoO_6 octahedra in Na_xCoO_2*yH_2O
• Shubnikov de Haas effect in the metallic state of Na${}_{0.3}$CoO${}_2$
• Deformation of Electronic Structures Due to CoO6 Distortion and Phase Diagrams of NaxCoO2.yH2O
• Na${}_x$CoO${}_2$ in the x -> 0 Regime: Coupling of Structure and Correlation effects
• Electronic structure and Fermi surface tolopogy of Na${}_x$CoO${}_2$
• Influence of water intercalation on the electronic structure of the hydrated Na0.3CoO2.yH2O using a local spin density approximation

Cited by in corpus (6)

• The low-energy ARPES and heat capacity of Na${}_{0.3}$CoO${}_2$: A DMFT study
• Calculating electron momentum densities and Compton profiles using the linear tetrahedron method
• Coulomb correlations do not fill the e'_g hole pockets in Na_{0.3}CoO_2
• The electronic structure of the Na${}_x$CoO${}_2$ surface
• Spin fluctuations, magnetic long-range order and Fermi surface gapping in NaxCoO2
• Hall effect on the triangular lattice