– Part II: Theory*

The honeycomb cobaltates are pseudospin-1/2 materials known for their highly anisotropic and bond-dependent magnetic couplings, which have been recently highlighted as potential Kitaev materials. In this contribution, we discuss the stacked honeycomb material Na₂Co₂TeO₆, for which a variety of magnetic models have been proposed on the basis of neutron scattering[1,2] and electron spin resonance measurements[3]. Combining ab-initio calculations with modeling of the neutron scattering and infrared / ESR (part I) experiments, we present a complete picture of the magnetic Hamiltonian and excitations. The effect of disorder of inter-layer Na ions on Co-Co magnetic coupling will also be discussed.

[1] W. Yao, et al., Phys. Rev. Lett. 129, 147202 (2022)

[2] W. Chen, et al., Phys. Rev. B 103, L180404 (2021)

[3] G. Lin, et al., Nat. Commun.12, 1-8 (2021)