Dominant Kitaev interactions in the honeycomb materials Na3Co2SbO6 and Na2Co2TeO6
Abstract
Cobaltates with 3d based layered honeycomb structure were recently proposed as Kitaev magnets and putative candidates to host the long-sought Kitaev spin liquid. Here we present inelastic neutron scattering results down to 50 mK for powder samples of Na3Co2SbO6 and Na2Co2TeO6, with high resolution in regions of low momentum and energy transfers. We compare the experimental data below the antiferromagnetic zigzag ordering temperature with dynamical structure factors obtained within spin wave theory. We search the wide parameter range of a K-J1---J3 spin 1/2 model and identify the best fits to constant momentum cuts of the inelastic neutron data. The powder average limits the selection of a unique parameter set for each material, but we see clear trends towards ferromagnetic Kitaev exchange in both compounds, and ratios |K/J1| could be as large as 5… 25; in contrast, antiferromagnetic Kitaev exchange cannot be ruled out, but requires a fine-tuning of all involved spin exchange couplings with only moderate ratio |K/J1| 1. Our experimental data are incompatible with a purely isotropic Heisenberg model.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.