Relevance of on-site and intersite Coulomb interactions in the Kitaev-Heisenberg magnet Na${}_3$Co${}_2$SbO${}_6$

Abstract

The detection of considerable spin frustration in honeycomb cobalt oxide compounds indicates the presence of sizable Kitaev interactions in these systems, enlarging the pool of Kitaev spin liquid candidates. Several key questions remain to be answered, as basic as the mechanisms behind Kitaev couplings in Co${}^{2+}$ $t_{2g}^5{e}_g^2$ magnets. Analyzing the quantum chemistry of interacting magnetic moments in Na${}_3$Co${}_2$SbO${}_6$, a representative $LS$-coupled $t_{2g}^5{e}_g^2$ oxide, we find that the Kitaev and off-diagonal $\Gamma$ interactions are substantial and antiferromagnetic but somewhat weaker than the Heisenberg contribution. All nearest-neighbor couplings feature massive contributions from direct Coulomb exchange and/or on-site multiconfigurational dressing, mechanisms not considered so far in descriptive models of Kitaev-Heisenberg magnetism. These findings call for systematic wave-function quantum chemical studies in order to understand direct-indirect exchange synergies in Kitaev-Heisenberg magnets and how to possibly tune intersite couplings towards the Kitaev spin liquid ground state.

References in corpus (23)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Models and Materials for Generalized Kitaev Magnetism
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Kitaev-Heisenberg Hamiltonian for High-Spin $d^7$ Mott Insulators
• Hidden symmetries of the extended Kitaev-Heisenberg model: Implications for honeycomb lattice iridates A2IrO3
• Microscopic mechanism for higher-spin Kitaev model
• Kitaev interactions in the Co honeycomb antiferromagnets Na${}_3$Co${}_2$SbO${}_6$ and Na${}_2$Co${}_2$TeO${}_6$
• Antiferromagnetic Kitaev interaction in $J_\rm{eff}=1/2$ cobalt honeycomb materials Na${}_3$Co${}_2$SbO${}_6$ and Na${}_2$Co${}_2$TeO${}_6$
• Magnetic order in single crystals of Na3Co2SbO6 with a honeycomb arrangement of 3d${}^7$ Co${}^{2+}$ ions
• Dominant Kitaev interactions in the honeycomb materials Na${}_3$Co${}_2$SbO${}_6$ and Na${}_2$Co${}_2$TeO${}_6$
• Magnetic Couplings in Edge-Sharing High-Spin $d^7$ Compounds
• Giant magnetic in-plane anisotropy and competing instabilities in Na3Co2SbO6
• Non-Kitaev vs. Kitaev Honeycomb Cobaltates
• Triple-q order in Na${}_2$Co${}_2$TeO${}_6$ from proximity to hidden-SU(2)-symmetric point
• Spin-state transition and spin-polaron physics in cobalt oxide perovskites: ab initio approach based on quantum chemical methods
• Easy-plane multi-$\mathbf{q}$ magnetic ground state of Na${}_3$Co${}_2$SbO${}_6$
• Spin vestigial orders in extended Heisenberg-Kitaev models near hidden SU(2) points: Application to Na${}_2$Co${}_2$TeO${}_6$
• NaRuO${}_2$: Kitaev-Heisenberg exchange in triangular-lattice setting
• Ring-Exchange Interaction Effects on Magnons in Dirac Magnet CoTiO${}_3$
• Resonating holes vs molecular spin-orbit coupled states in group-5 lacunar spinels
• Static magnetic and ESR spectroscopic properties of the dimer-chain antiferromagnet BiCoPO${}_5$
• On the multi-$\mathbf{q}$ characteristics of magnetic ground states of honeycomb cobalt oxides
• Anisotropic Coulomb exchange as source of Kitaev and off-diagonal symmetric anisotropic couplings