Competing Antiferromagnetic-Ferromagnetic States in $d^7$ Kitaev Honeycomb Magnet

Abstract

The Kitaev model is a rare example of an analytically solvable and physically instantiable Hamiltonian yielding a topological quantum spin liquid ground state. Here we report signatures of Kitaev spin liquid physics in the honeycomb magnet $L{i}_{3}C{o}_{2}Sb{O}_6$, built of high-spin $d^7$ ($C{o}^{2+}$) ions, in contrast to the more typical low-spin $d^5$ electron configurations in the presence of large spin-orbit coupling. Neutron powder diffraction measurements, heat capacity, and magnetization studies support the development of a long-range antiferromagnetic order space group of $C_{C}2/m$, below $T_N$ = 11 K at ${\mu }_{0}H$ = 0 T. The magnetic entropy recovered between $T$ = 2 K and 50 K is estimated to be 0.6Rln2, in good agreement with the value expected for systems close to a Kitaev quantum spin liquid state. The temperature-dependent magnetic order parameter demonstrates a $\beta$ value of 0.19(3), consistent with XY anisotropy and in-plane ordering, with Ising-like interactions between layers. Further, we observe a spin-flop driven crossover to ferromagnetic order with space group of $C2/m$ under an applied magnetic field of ${\mu }_{0}H$ $\approx$ 0.7 T at $T$ = 2 K. Magnetic structure analysis demonstrates these magnetic states are competing at finite applied magnetic fields even below the spin-flop transition. Both the $d^7$ compass model, a quantitative comparison of the specific heat of $L{i}_{3}C{o}_{2}Sb{O}_6$, and related honeycomb cobaltates to the anisotropic Kitaev model further support proximity to a Kitaev spin liquid state. This material demonstrates the rich playground of high-spin $d^7$ systems for spin liquid candidates, and complements known $d^5$ Ir- and Ru-based materials.

arXiv comment16 pages, 8 figures

References in corpus (34)

• 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
• Proximate Kitaev Quantum Spin Liquid Behaviour in α-RuCl${}_3$
• $\alpha$-RuCl3: a Spin-Orbit Assisted Mott Insulator on a Honeycomb Lattice
• Herbertsmithite and the Search for the Quantum Spin Liquid
• On the Origin of Zigzag Magnetic Order in Iridium Oxide Na2IrO3
• Hyper-honeycomb iridate $\beta$-Li2IrO3 as a platform for Kitaev magnetism
• Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Kitaev-Heisenberg Hamiltonian for High-Spin $d^7$ Mott Insulators
• Kitaev Spin Liquid in 3d Transition Metal Compounds
• Universal Window for Two Dimensional Critical Exponents
• Magnetic properties of the honeycomb oxide Na${}_2$Co${}_2$TeO${}_6$
• Scaling and data collapse from local moments in frustrated disordered quantum spin systems
• Zigzag antiferromagnetic ground state with anisotropic correlation lengths in the quasi-2D honeycomb lattice compound Na2Co2TeO6
• Rethinking $\alpha$-RuCl${}_3$
• Clues and criteria for designing Kitaev spin liquid revealed by thermal and spin excitations of honeycomb iridates Na${}_2$IrO${}_3$
• Ferrimagnetism and anisotropic phase tunability by magnetic fields in Na${}_2$Co${}_2$TeO${}_6$
• Magnetic order in single crystals of Na3Co2SbO6 with a honeycomb arrangement of 3d${}^7$ Co${}^{2+}$ ions
• Thermodynamic Evidence of Proximity to a Kitaev Spin-Liquid in Ag${}_3$LiIr${}_2$O${}_6$
• Optically Driven Magnetic Phase Transition of Monolayer RuCl3
• Exotic low-energy excitations emergent in the random Kitaev magnet Cu${}_2$IrO${}_3$
• Incipient and well-developed entropy plateaus in spin-S Kitaev models
• Pressure-induced melting of magnetic order and emergence of new quantum state in alpha-RuCl3
• Impact of off-diagonal exchange interactions on the Kitaev spin liquid state of $\alpha$-RuCl${}_3$
• Orbitally induced hierarchy of exchange interactions in zigzag antiferromagnetic state of honeycomb silver delafossite Ag3Co2SbO6
• Spin dynamics in the S =1/2 kagome compound vesignieite, Cu3Ba(VO5H)2
• Synthesis, structure and magnetic properties of honeycomb-layered Li3Co2SbO6 with new data on its sodium precursor, Na3Co2SbO6
• Single crystal growth of Cu4(OH)6BrF and universal behavior in quantum spin liquid candidates synthetic barlowite and herbertsmithite
• Spin excitations of a proximate Kitaev quantum spin liquid realized in Cu${}_2$IrO${}_3$
• Spin dynamics and field-induced magnetic phase transition in the honeycomb Kitaev magnet $\alpha$-Li${}_2$IrO${}_3$
• Local spin structure of the $\alpha$-RuCl${}_3$ honeycomb-lattice magnet observed via muon spin rotation/relaxation
• Low temperature enhancement of ferromagnetic Kitaev correlations in α-RuCl3
• Large off diagonal exchange couplings and spin liquid states in ${\mathbf{C}}_3$ symmetric iridates

Cited by in corpus (21)

• Geometrical frustration versus Kitaev interactions in BaCo${}_2$(AsO${}_4$)${}_2$
• Static and dynamic magnetic properties of honeycomb lattice antiferromagnets Na${}_2{M}_2$TeO${}_6$, $M$ = Co and Ni
• Dominant Kitaev interactions in the honeycomb materials Na${}_3$Co${}_2$SbO${}_6$ and Na${}_2$Co${}_2$TeO${}_6$
• Beyond Kitaev physics in strong spin-orbit coupled magnets
• A magnetic continuum observed by terahertz spectroscopy in a quantum spin liquid candidate BaCo${}_2$(AsO${}_4$)${}_2$
• Unusual heat transport of the Kitaev material Na${}_2$Co${}_2$TeO${}_6$: putative quantum spin liquid and low-energy spin excitations
• Duality and domain wall dynamics in a twisted Kitaev chain
• Spin-orbital entangled state and realization of Kitaev physics in 3d cobalt compounds: a progress report
• Non-Kitaev vs. Kitaev Honeycomb Cobaltates
• Towards Kitaev Spin Liquid in 3d Transition Metal Compounds
• Magnetic excitations of the field induced states in BaCo2(AsO4)2 probed by time-domain terahertz spectroscopy
• Single-ion properties of the transverse-field Ising model material CoNb${}_2$O${}_6$
• Antiferro- and Meta-magnetism in the S=7/2 Hollandite Analog EuGa2Sb2
• CaCo${}_2$TeO${}_6$: A topochemically prepared 3$d^7$ honeycomb Kitaev magnet
• Strain-induced phase diagram of the $S=\frac{3}{2}$ Kitaev material $\mathrm{CrSiT}{\mathrm{e}}_3$
• Anomalous ferromagnetic behavior in the orthorhombic Li${}_3$Co${}_2$SbO${}_6$
• Proximity-induced sequence of field transitions in Kitaev candidate BaCo${}_2$(AsO${}_4$)${}_2$
• Polymorphism and Magnetism in a Kitaev Honeycomb Cobaltate KCoAsO${}_4$
• Coexistence of static and dynamic local magnetic fields in an S = 3/2 honeycomb lattice antiferromagnet Co2Te3O8
• More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions
• Nesting instability of gapless U(1) spin liquids with spinon Fermi pockets in two dimensions