Deformation of Electronic Structures Due to CoO6 Distortion and Phase Diagrams of NaxCoO2.yH2O

Abstract

Motivated by recently reported experimental phase diagrams, we study the effects of CoO6 distortion on the electronic structure in NaxCoO2.yH2O. We construct the multiband tight-binding model by employing the LDA result. Analyzing this model, we show the deformation of band dispersions and Fermi-surface topology as functions of CoO2-layer thickness. Considering these results together with previous theoretical ones, we propose a possible schematic phase diagram with three successive phases: the extended s-wave superconductivity (SC), the magnetic order, and the spin-triplet SC phases when the Co valence number s is +3.4. A phase diagram with only one phase of spin-triplet SC is also proposed for the s=+3.5 case.

arXiv comment4 pages, 5 figures

References in corpus (21)

• Superconductivity Phase Diagram of Na(x)CoO(2).1.3H(2)O
• Unconventional Superconductivity and Electron Correlations in Cobalt Oxyhydrate Na${}_{0.35}$CoO${}_2$$\cdot y$H${}_2$O
• Crystal Structure of the Sodium Cobaltate Deuterate Superconductor NaxCoO2o4xD2O (x=1/3)
• Structure and Dynamics of Superconducting NaxCoO(2) Hydrate and Its Unhydrated Analog
• Unconventional Superconductivity and Nearly Ferromagnetic Spin Fluctuations in Na${}_x$CoO${}_2$$\cdot y$H${}_2$O
• Ferromagnetic fluctuation and possible triplet superconductivity in Na_xCoO_2*yH_2O: Fluctuation-exchange study of multi-orbital Hubbard model
• Possible spin-triplet $f$-wave pairing due to disconnected Fermi surfaces in Na${}_x$CoO${}_2\cdot y$H${}_2$O
• The crystal growth and characterization of NaxCoO2 and NaxCoO2yH2O
• 59Co-NMR Knight Shift of the Superconducting NaxCoO2.yH2O
• Spin singlet pairing in the superconducting state of NaxCoO2\cdot1.3H2O: evidence from a ^{59}Co Knight shift in a single crystal
• Revised superconducting phase diagram of hole doped Na${}_x$(H${}_3$O)${}_z$CoO${}_2\cdot y$H${}_2$O
• Multi-orbital analysis on the Superconductivity in Na_{x}CoO_{2} \cdot y H_{2}O
• Spin-Dynamics in the Carrier-Doped $S=1/2$ Triangular-Lattice of Na${}_x$CoO${}_2$-yH${}_2$O
• Weak Magnetic Order in the Bilayered-hydrate Na${}_x$CoO${}_2\cdot y$H${}_2$O Structure Probed by Co Nuclear Quadrupole Resonance - Proposed Phase Diagram in Superconducting Na${}_x$CoO${}_2\cdot$ $y$H${}_2$O
• 59Co-NMR Knight Shift of Aligned Crystals and Polycrystalline Samples of Superconducting Na0.3CoO2.1.3H2O
• 59Co Nuclear Quadrupole Resonance Studies of Superconducting and Non-superconducting Bilayer Water Intercalated Sodium Cobalt Oxides NaxCoO2.yH2O
• Ferromagnetic and triplet-pairing instabilities controlled by the trigonal distortion of the CoO_6 octahedra in Na_xCoO_2*yH_2O
• Electron-Phonon mechanism for Superconductivity in Na${}_{0.35}$CoO${}_2$: Valence-Band Suhl-Kondo effect Driven by Shear Phonons
• Correlation between Superconducting Transition Temperature $T_c$ and Increase of Nuclear Spin-Lattice Relaxation Rate Devided by Temperature $1/T_{1}T$ at $T_c$ in the Hydrate Cobaltate Na${}_x$CoO${}_2\cdot y$H${}_2$O
• Correlation between Tc and Lattice Parameters of Novel Superconducting NaxCoO2 yH2O
• Search for Magnetic Excitation Spectra of NaxCoO2.yD2O -Neutron Scattering-

Cited by in corpus (10)

• "Pudding mold" band drives large thermopower in Na${}_x$CoO${}_2$
• Elliptical hole pockets in the Fermi surfaces of unhydrated and hydrated sodium cobalt oxides
• Precise Control of Band Filling in NaxCoO2
• Efficient fluctuation exchange approach to low-temperature spin fluctuations and superconductivity: from the Hubbard model to Na${}_x$CoO${}_2\cdot y$H${}_2$O
• A unified origin for the 3D magnetism and superconductivity in Na${}_x$CoO${}_2$
• Fermiology via the electron momentum distribution
• CoO2-Layer-Thickness Dependence of Magnetic Properties and Possible Two Different Superconducting States in NaxCoO2.yH2O
• Co-NMR Knight Shift of NaxCoO2 \dot yH2O Studied in Both Superconducting Regions of the Tc-nuQ3 Phase Diagram Divided by the Nonsuperconducting Phase
• Specific Heat and Superfluid Density for Possible Two Different Superconducting States in NaxCoO2.yH2O
• 59Co, 23Na, and 1H NMR Studies of Double-Layer Hydrated Superconductors NaxCoO2-yH2O