Comparison of the Electronic Structures of Hydrated and Unhydrated Na_xCoO_2: The Effect of H_2O

TL;DR

This study uses density functional theory to compare the electronic structures of hydrated and unhydrated Na_xCoO_2, revealing minimal changes in the Fermi surface due to water intercalation, mainly affecting dimensionality.

Contribution

It provides a detailed computational comparison showing water intercalation has limited impact on the electronic structure of Na_xCoO_2, highlighting their close electronic relationship.

Findings

Water intercalation causes minimal changes to the Fermi surface.

Hydration increases the two-dimensionality of the electronic structure.

Electronic properties of hydrated and unhydrated phases are closely connected.

Abstract

We report electronic structure calculations within density functional theory for the hydrated superconductor Na_{1/3}CoO_2(1.33)H_2O and compare the results with the parent compound Na_{0.3}CoO_2. We find that the intercalation of water into the parent compound has little effect on the Fermi surface outside of the predictable effects expansion, in particular increased two-dimensionality. This implies an intimate connection between the electronic properties of the hydrated and unhydrated phases.