Why the magnetic interactions in Na_xCoO₂ are 3D

2004/12/23 by M. D. Johannes, I. I. Mazin, Johannes, M. D. +4
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el

paper · pdf · doi:10.48550/arxiv.cond-mat/0412663

4 pages

arxiv created 2004/12/23 · openalex publication_date 2004/12/23 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The puzzle of 3D magnetic interactions in the structurally 2D layered oxide Na_xCoO₂ is addressed using first principles calculations and analysis of the exchange mechanisms. The calculations agree with recent neutron results, favoring AFM stacking of FM planes. Superexchange via direct O-O hopping and through intermediate Na sp² hybrids couples each Co to its nearest and six next-nearest interplanar neighbors equally. The individual exchange constants are rather 2D, like the lattice itself, but due to multiple c-axis exchange paths, the magnetism becomes effectively 3D.

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