Doping effects on the electronic and structural properties of CoO2: An LSDA+U study

Abstract

A systematic LSDA+U study of doping effects on the electronic and structural properties of single layer CoO2 is presented. Undoped CoO2 is a charge transfer insulator within LSDA+U and a metal with a high density of states (DOS) at the Fermi level within LSDA. (CoO2)${}^{1.0-}$, on the other hand, is a band insulator with a gap of 2.2 eV. Systems with fractional doping are metals if no charge orderings are present. Due to the strong interaction between the doped electron and other correlated Co d electrons, the calculated electronic structure of (CoO2)${}^{x-}$ depends sensitively on the doping level x. Zone center optical phonon energies are calculated under the frozen phonon approximation and are in good agreement with measured values. Softening of the $E_g$ phonon at doping x ~0.25 seems to indicate a strong electron-phonon coupling in this system. Possible intemediate spin states of Co ions, Na ordering, as well as magnetic and charge orderings in this system are also discussed.

11 pages, 12 figures

References in corpus (9)

• Spin entropy as the likely source of enhanced thermopower in $\rm\bf Na_xCo_2O_4
• Correlated metals and the LDA+U method
• Superconductivity Phase Diagram of Na(x)CoO(2).1.3H(2)O
• An Electronic Model for $Co{O}_2$ layer based systems: Chiral RVB metal and Superconductivity
• Unconventional magnetic transition and transport behavior in Na0.75CoO2
• Structure and Dynamics of Superconducting NaxCoO(2) Hydrate and Its Unhydrated Analog
• Static magnetic order in Na${}_{0.75}$CoO${}_2$ detected by muon spin rotation and relaxation
• Possible spin triplet superconductivity in Na${}_x$CoO${}_2\cdot y$H${}_2$0
• Raman Phonons and Ageing-Related Surface Disorder in NaxCoO2

Cited by in corpus (25)

• Theory of Sodium Ordering in NaxCoO2
• Single Mott Transition in Multi-Orbital Hubbard Model
• Orbital Symmetry and Electron Correlation in Na_{x}CoO_2
• Synthesis and properties of CoO2, the x = 0 end member of the LixCoO2 and NaxCoO2 systems
• The Fermi surface of Na${}_x$CoO${}_2$
• Effect of Dynamical Coulomb Correlations on the Fermi Surface of Na_0.3CoO_2
• Electronic Correlations in CoO2, the Parent Compound of Triangular Cobaltates
• Disproportionation Transition at Critical Interaction Strength: Na${}_{1/2}$CoO${}_2$
• Na content dependence of superconductivity and the spin correlations in Na_{x}CoO_{2}\cdot 1.3H_{2}O
• Phase Diagram of Na${}_x$CoO${}_2$ Studied by Gutzwiller Density Functional Theory
• Origin of magnetism and quasiparticles properties in Cr-doped TiO${}_2$
• Na${}_x$CoO${}_2$ in the x -> 0 Regime: Coupling of Structure and Correlation effects
• Compositional phase stability of correlated electron materials within DFT+DMFT
• Optical Study of the Electronic Structure and Correlation Effects in K0.49RhO2
• Theoretical analysis of oxygen vacancies in layered sodium cobaltate Na_xCoO_{2-δ}
• Electronic Structure of Sodium Cobalt Oxide: Comparing Mono- and Bilayer-hydrate
• Dopant incorporation site in sodium cobaltate's host lattice: A critical factor for thermoelectric performance
• Pressure effects in the triangular layered cobaltites NaxCoO2
• Origin of the electron disproportionation in the metallic sodium cobaltates
• Effect of Ti doping on the electrical transport and magnetic properties of layered compound Na0.8CoO2
• Comparison of the Electronic Structures of Two Non-cuprate Layered Transition Metal Oxide Superconductors
• Phonon softening and "forbidden" mode observed by Raman scattering in Na0.5CoO2
• Interplay between mesoscopic phase separation and bulk magnetism in the layered NaxCoO2
• Influence of water intercalation on the electronic structure of the hydrated Na0.3CoO2.yH2O using a local spin density approximation
• A first principles study on FeAs single layers