Electronic Structure of Sodium Cobalt Oxide: Comparing Mono- and Bilayer-hydrate

Abstract

To shed new light on the mechanism of superconductivity in sodium cobalt oxide bilayer-hydrate (BLH), we perform a density functional calculation with full structure optimization for BLH and its related nonsuperconducting phase, monolayer hydrate (MLH). We find that these hydrates have similar band structures, but a notable difference can be seen in the $a_{1g}$ band around the Fermi level. While its dispersion in the $z$ direction is negligibly small for BLH, it is of the order of 0.1 eV for MLH. This result implies that the three dimensional feature of the $a_{1g}$ band may be the origin for the absence of superconductivity in MLH.

5 pages, 7 figures, to be published in Phys. Rev. B

References in corpus (6)

• Charge Disproportionation and Spin Ordering Tendencies in Na(x)CoO2
• Possible spin-triplet $f$-wave pairing due to disconnected Fermi surfaces in Na${}_x$CoO${}_2\cdot y$H${}_2$O
• Doping effects on the electronic and structural properties of CoO2: An LSDA+U study
• Nesting, spin-fluctuations, and odd-gap superconductivity in NaxCoO2 yH2O
• The Role of hybridization in NaxCoO2 and the Effect of Hydration
• Competition between singlet and triplet pairings in Na_xCoO_2 yH_2O

Cited by in corpus (5)

• Unconventional Superconductivity Induced by Quantum Critical Fluctuations in Hydrate Cobaltate Na${}_x$(H${}_3$O)${}_z$CoO${}_x\cdot$ $y$H${}_2$O -- Relationship between Magnetic Fluctuations and the Superconductivity Revealed by a Co Nuclear Quadrupole Resonance --
• Role of spin-orbit coupling on the spin triplet pairing in Na_{x}CoO_{2}yH_{2}O I: d-vector under zero magnetic field
• Role of spin-orbit coupling on the spin triplet pairing in Na_{x}CoO_{2}yH_{2}O II: Multiple phase diagram under the magnetic field
• Chemical Differences between K and Na in Alkali Cobaltates
• Influence of water intercalation on the electronic structure of the hydrated Na0.3CoO2.yH2O using a local spin density approximation