Disproportionation and Critical Interaction Strength in Na${}_x$CoO${}_2$: Concentration Dependence

Abstract

We present results of studies of charge disproportionation (CD) and spin differentiation in Na${}_x$CoO${}_2$ using the correlated band theory approach (local-density approximation+Hubbard U:LDA+U). The simultaneous CD and gap opening can be followed through a first order charge disproportionation transition. By comparison with experiments, we propose a value of the Coulomb repulsion strength U($x$) that has significant dependence on the carrier concentration $x$, for which we obtain a phase diagram. The connection between the oxygen height and effects of on-site correlation is also reported.

3 pages with 4 embedded figures. submitted to proceedings in 2005 50th MMM conference

References in corpus (3)

• Three-Dimensional Spin Fluctuations in Na0.75CoO2
• Disproportionation Transition at Critical Interaction Strength: Na${}_{1/2}$CoO${}_2$
• Na${}_x$CoO${}_2$ in the x -> 0 Regime: Coupling of Structure and Correlation effects

Cited by in corpus (1)

• NaV2O4: a Quasi-1D Metallic Antiferromagnet with Half-Metallic Chains