Na Induced Correlations in Na${}_x$CoO${}_2$

Abstract

Increasing experimental evidence is building which indicates that signatures of strong correlations are present in the Na rich region of Na${}_x$CoO${}_2$ (ie. $x\approx 0.7$) and absent in the Na poor region (ie. $x\approx 0.3$). This is unexpected given that NaCoO${}_2$ is a band insulator and CoO${}_2$ has an integer filled open shell making it a candidate for strong correlations. We explain these experimental observations by presenting a minimal low-energy Hamiltonian for the cobaltates and solving it within LDA+DMFT. The Na potential is shown to be a key element in understanding correlations in this material. Furthermore, LDA calculations for the realistic Na ordering predict a \emph{binary} perturbation of the Co sites which correlates with the Na${}_1$ sites (ie. Na sites above/below Co sites).

References in corpus (11)

• Electronic Structure Calculations with Dynamical Mean-Field Theory: A Spectral Density Functional Approach
• Charge-ordering, commensurability and metallicity in the phase diagram of layered Na(x)CoO(2)
• Ferromagnetic in-plane spin fluctuations in NaxCoO2 observed by neutron inelastic scattering
• Possible effects of charge frustration in Na${}_x$CoO${}_2$: bandwidth suppression, charge orders and resurrected RVB superconductivity
• 59Co NMR study of the Co states in superconducting and anhydrous cobaltates
• The Role of hybridization in NaxCoO2 and the Effect of Hydration
• Evidence of a single nonmagnetic Co3+ state in the Na1CoO2 cobaltate
• Magnetic susceptibility study of hydrated and non-hydrated NaxCoO2-yH2O single crystals
• Ferromagnetism and Metal-Insulator Transition in the Disordered Hubbard Model
• Non-magnetic insulator state in Na1CoO2 and phase separation of Na vacancies
• Magnetic Fluctuations in the Metallic State of Na${}_{0.7}$CoO${}_2$ Revealed by ${}^{23}$Na NMR

Cited by in corpus (43)

• Sodium vacancy ordering and the co-existence of localized spins and itinerant charges in NaxCoO2
• Spin correlations and cobalt charge states: A new phase diagram of sodium cobaltates
• Electronic texture of the thermoelectric oxide Na0.75CoO2
• Na ordering imprints a metallic kagome lattice onto the Co planes of Na2/3CoO2
• Can disorder alone destroy the eg' hole pockets of NaxCoO2? A Wannier function based first-principles method for disordered systems
• Na atomic order, Co charge disproportionation and magnetism in Na${}_x$CoO${}_2$ for large Na contents
• Interplay between magnetic properties and thermoelectricity in misfit and Na cobaltates
• Enhancement of the Na${}_x$CoO${}_2$ thermopower due to electronic correlations
• Competing orders in Na${}_x$CoO${}_2$ from strong correlations on a two-particle level
• Local moment, itinerancy and deviation from Fermi liquid behavior in Na${}_x$CoO${}_2$ for $0.71\le x\le 0.84$
• The low-energy ARPES and heat capacity of Na${}_{0.3}$CoO${}_2$: A DMFT study
• Direct observation of strong correlations near the band insulator regime of Bi misfit cobaltates
• GdI_2: A New Ferromagnetic Excitonic Solid?
• Correlation effects on the doped triangular lattice in view of the physics of sodium-rich Na${}_x$CoO${}_2$
• The origin of strong correlations and superconductivity in Na${}_x$CoO${}_2$
• Magnetic fluctuations and specific heat in NaxCoO2 near a Lifshitz topological transition
• Effects of electronic correlations and disorder on the thermopower of NaxCoO2
• Magnetoresistance scaling in the layered cobaltate Ca3Co4O9
• Experimental study of the incoherent spectral weight in the photoemission spectra of the misfit cobaltate [Bi2Ba2O4][CoO2]2
• Strong correlations enhanced by charge-ordering in highly doped cobaltates
• Theoretical analysis of oxygen vacancies in layered sodium cobaltate Na_xCoO_{2-δ}
• Sodium Trimer Ordering on NaxCoO2 Surface
• Itinerant and localized magnetism on the triangular lattice: sodium rich phases of Na${}_x$CoO${}_2$
• Rearrangement of Sodium ordering and its effect on physical properties in $N{a}_{x}Co{O}_2$ system
• Selecting the suitable dopants: electronic structures of transition metal and rare earth doped thermoelectric sodium cobaltate
• Electron-phonon interaction in the lamellar cobaltate Na${}_x$CoO${}_2$
• Considerable non-local electronic correlations in strongly doped Na${}_x$CoO${}_2$
• Interplay of frustration, magnetism, charge ordering, and covalency in a model of Na0.5CoO2
• The origin of a${}_{1g}$ and e${}_g$' orderings in Na${}_x$CoO${}_2$
• Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration
• High frequency thermoelectric response in correlated electronic systems
• Emergent charge ordering in near half doped Na${}_{0.46}$CoO${}_2$
• Ionic Hubbard model on a triangular lattice for Na_0.5CoO_2, Rb_0.5CoO_2 and K_0.5CoO_2: Mean-field slave boson theory
• Theory of carrier concentration-dependent electronic behavior in layered cobaltates
• Origin of the electron disproportionation in the metallic sodium cobaltates
• New electronic orderings observed in cobaltates under the influence of misfit periodicities
• Electronic and magnetic properties of the ionic Hubbard model on the striped triangular lattice at 3/4 filling
• Mott and Wigner-Mott transitions in doped correlated electron systems: effects of superlattice potential and inter-site correlation
• Evidence for Oxygen Holes due to d-p Rehybridization in Thermoelectric Sr_{1-x}Rh_{2}O_{4}
• Enhancement of the effective disorder potential and the thermopower in Na${}_x$CoO${}_2$ through the electron-phonon coupling
• Ab-initio studying of spin states of sodium cobaltate Na${}_{2/3}$CoO${}_2$
• Statistical fluxes and the Curie-Weiss metal state
• Temperature-driven sodium-ion dynamical-to-static crossover in the zig-zag ordered phase of Na${}_{0.5}$CoO${}_2$