Trigonal distortion in the Kitaev candidate honeycomb magnet BaCo2(AsO4)2

Abstract

We conducted x-ray absorption (XAS) and magnetic circular dichroism (XMCD) measurements at the Co $L_{2,3}$ edges on single crystals of the Kitaev candidate honeycomb lattice compound BaCo${}_2$(AsO${}_4$)${}_2$. The measurements employed the inverse partial fluorescence yield technique, which is ideal for acquiring reliable x-ray absorption spectra from highly insulating samples, enabling precise quantitative analysis. Our experimental results revealed a significant linear dichroic signal, indicating strong trigonal distortion in the CoO${}_6$ octahedra in BaCo${}_2$(AsO${}_4$)${}_2$. We performed a detailed analysis of the experimental XAS and XMCD spectra using a full-multiplet configuration-interaction cluster model. This analysis unveiled that the $t_{2g}$ hole density is predominantly localized in the $a_{1g}$ orbital. Through XMCD sum rules and theoretical calculations, we quantified both the spin and orbital magnetic moments. Our study demonstrates that the local electronic structure of the CoO${}_6$ octahedra displays an effective trigonal distortion of approximately $-0.114$ eV. This distortion is larger than the Co $3d$ spin-orbit coupling constant, emphasizing the crucial impact of local structural distortions on the electronic and magnetic properties of BaCo${}_2$(AsO${}_4$)${}_2$.

References in corpus (37)

• Anyons in an exactly solved model and beyond
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Quantum Spin Liquids
• Kitaev-Heisenberg Model on Honeycomb Lattice: Possible Exotic Phases in Iridium Oxides $A_2$IrO${}_3$
• Kitaev quantum spin liquid - concept and materialization
• Models and Materials for Generalized Kitaev Magnetism
• The monoclinic crystal structure of $\alpha$-RuCl${}_3$ and the zigzag antiferromagnetic ground state
• Multiplet ligand-field theory using Wannier orbitals
• Evidence for a Field-induced Quantum Spin Liquid in $\alpha$-RuCl${}_3$
• Excitations in the field-induced quantum spin liquid state of alpha-RuCl3
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Efficient real frequency solver for dynamical mean field theory
• Bulk sensitive x-ray absorption spectroscopy free of self-absorption effects
• Kitaev Spin Liquid in 3d Transition Metal Compounds
• Local electronic structure and magnetic properties of LaMn0.5Co0.5O3 studied by x-ray absorption and magnetic circular dichroism spectroscopy
• Valence, spin, and orbital state of the Co ions in the one-dimensional Ca3Co2O6: an x-ray absorption and magnetic circular dichroism study
• Controlling orbital moment and spin orientation in CoO layers by strain
• Weak-field induced nonmagnetic state in a Co-based honeycomb
• Bands, resonances, edge singularities and excitons in core level spectroscopy investigated within the dynamical mean field theory
• Spin-orbit coupling and crystal-field distortions for a low-spin $3d^5$ state in BaCoO${}_3$
• Geometrical frustration versus Kitaev interactions in BaCo${}_2$(AsO${}_4$)${}_2$
• Determination of total x-ray absorption coefficient using non-resonant x-ray emission
• A magnetic continuum observed by terahertz spectroscopy in a quantum spin liquid candidate BaCo${}_2$(AsO${}_4$)${}_2$
• XY magnetism, Kitaev exchange, and long-range frustration in the $J_{\mathrm{eff}}=1/2$ honeycomb cobaltates
• Magnetic Couplings in Edge-Sharing High-Spin $d^7$ Compounds
• Spin-orbital entangled state and realization of Kitaev physics in 3d cobalt compounds: a progress report
• Ab initio guided minimal model for the "Kitaev" material BaCo${}_2$(AsO${}_4$)${}_2$: Importance of direct hopping, third-neighbor exchange and quantum fluctuations
• Non-Kitaev vs. Kitaev Honeycomb Cobaltates
• Polarized-neutron investigation of magnetic ordering and spin dynamics in BaCo${}_2$(AsO${}_4$)${}_2$ frustrated honeycomb-lattice magnet
• Magnetic excitations of the field induced states in BaCo2(AsO4)2 probed by time-domain terahertz spectroscopy
• Probing the $J_{eff}=0$ ground state and the Van Vleck paramagnetism of the Ir${}^{5+}$ ions in the layered Sr${}_2$Co${}_{0.5}$Ir${}_{0.5}$O${}_4$
• Comparative Raman Scattering Study of Crystal Field Excitations in Co-based Quantum Magnets
• Suppression of Antiferromagnetic Order by Strain in Honeycomb Cobaltate: Implication for Quantum Spin Liquid
• BaCo${}_2$(AsO${}_4$)${}_2$: Strong Kitaev, After All
• Hydrostatic pressure effect on Co-based honeycomb magnet BaCo2(AsO4)2
• Intermediate field-induced phase of the honeycomb magnet BaCo${}_2$(AsO${}_4$)${}_2$
• Spin-orbit entangled moments and magnetic exchange interactions in cobalt-based honeycomb magnets BaCo${}_2$($X$O${}_4$)${}_2$ ($X$ = P, As, Sb)