Skip to content

Charge and Spin Ordering in Insulating Na0.5CoO2: Effects of Correlation and Symmetry

K. -W. Lee, W. E. Pickett

cond-mat.str-elarXiv:cond-mat/0510555

Abstract

Ab initio band theory including correlations due to intra-atomic repulsion is applied to study charge disproportionation and charge- and spin-ordering in insulating Na0.5CoO2. Various ordering patterns (zigzag and two striped) for four-Co supercells are analyzed before focusing on the observed "out-of-phase stripe" pattern of antiferromagnetic Co4+ spins along charge-ordered stripes. This pattern relieves frustration and shows distinct analogies with the cuprate layers: a bipartite lattice of antialigned spins, with axes at 90 degree angles. Substantial distinctions with cuprates are also discussed, including the tiny gap of a new variant of "charge transfer" type within the Co 3d system.

Create a lesson