Spin disorder state induced by Mg${}^{2+}$ doping in a Kitaev material Na${}_3$Co${}_2$SbO${}_6$

Abstract

Due to the dominant Kitaev exchange interactions, the cobaltate, Na${}_3$Co${}_2$SbO${}_6$, has been considered to be approximate to the Kitaev quantum spin liquid (QSL). Here, we investigate both magnetic dilution and chemical pressure effects of Na${}_3$Co${}_2$SbO${}_6$ by the substitutions of Mg${}^{2+}$ for Co${}^{2+}$ through the structural, optical, magnetic and thermodynamic measurements. No structural transition has been observed, and the bandgaps remain constant in all doping levels. Combining with the magnetic and thermodynamic measurements, we find that the antiferromagnetic transition temperature is continuously suppressed with increasing Mg doping levels and completely disappears at $x=0.2$. Interestingly, when the doping level $x$ is larger than 0.2, neither long-range magnetic order nor spin glass state has been detected, and the specific heat has a residual linear term at zero field. All features indicate that Na${}_3$(Co${}_{2-x}$Mg${}_x$)SbO${}_6$ system enters into a novel spin disorder (NSD) state.

21 pages, 8 figures, submitted to PRB

References in corpus (25)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
• Models and Materials for Generalized Kitaev Magnetism
• Projected wavefunction study of Spin-1/2 Heisenberg model on the Kagome lattice
• Magnetic order in $\alpha$-RuCl${}_3$: a honeycomb lattice quantum magnet with strong spin-orbit coupling
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Experimental identification of quantum spin liquids
• Kitaev-Heisenberg Hamiltonian for High-Spin $d^7$ Mott Insulators
• Strong quantum fluctuations in a quantum spin liquid candidate with a Co-based triangular lattice
• Magnetic order in single crystals of Na3Co2SbO6 with a honeycomb arrangement of 3d${}^7$ Co${}^{2+}$ ions
• Identification of Magnetic Interactions and High-field Quantum Spin Liquid in $\alpha$-RuCl${}_3$
• Ba8CoNb6O24: a spin-1/2 triangular-lattice Heisenberg antiferromagnet in the 2D limit
• Spin-orbital entangled state and realization of Kitaev physics in 3d cobalt compounds: a progress report
• Effect of nonmagnetic dilution in honeycomb lattice iridates Na${}_2$IrO${}_3$ and Li${}_2$IrO${}_3$
• Giant magnetic in-plane anisotropy and competing instabilities in Na3Co2SbO6
• Spin-glass state and reversed magnetic anisotropy induced by Cr doping in the Kitaev magnet $\alpha$-RuCl${}_3$
• Magnetic phase diagram and possible Kitaev-like behavior of honeycomb-lattice antimonate Na3Co2SbO6
• Investigation of the magnetoelastic coupling anisotropy in the Kitaev material $\alpha$-RuCl${}_3$
• Diluting a triangular-lattice spin liquid: Synthesis and characterization of NaYb${}_{1-x}$Lu${}_x$S${}_2$ single crystals
• Tracking the evolution from isolated dimers to many-body entanglement in NaLu${}_x$Yb${}_{1-x}$Se${}_2$
• Neutron spectroscopy evidence for a possible magnetic-field-induced gapless quantum-spin-liquid phase in a Kitaev material $\alpha$-RuCl${}_3$
• Suppression of the antiferromagnetic order by Zn doping in a possible Kitaev material Na${}_2$Co${}_2$TeO${}_6$
• Dilution of the magnetic lattice in the Kitaev candidate $\alpha$-RuCl${}_3$ by Rh${}^{3+}$ doping
• Signatures of a gapless quantum spin liquid in the Kitaev material Na${}_3$Co${}_{2-x}$Zn${}_x$SbO${}_6$
• Raman spectroscopy of Na${}_3$Co${}_2$SbO${}_6$