Spin-waves in 2D honeycomb lattice $XXZ$-type van der Waals antiferromagnet CoPS${}_3$

Abstract

The magnetic excitations in CoPS${}_3$, a two-dimensional van der Waals (vdW) antiferromagnet with spin $S=3/2$ on a honeycomb lattice, has been measured using powder inelastic neutron scattering. Clear dispersive spin waves are observed with a large spin gap of ~13 meV. The magnon spectra were fitted using an $XXZ$-type $J_1-J_2-J_3$ Heisenberg Hamiltonian with a single-ion anisotropy assuming no magnetic exchange between the honeycomb layers. The best-fit parameters show ferromagnetic exchange $J_1=-2.08$ meV and $J_2=-0.26$ meV for the nearest and second-nearest neighbors and a sizeable antiferromagnetic exchange $J_3=4.21$ meV for the third-nearest neighbor with the strong easy-axis anisotropy $K=-2.06$ meV. The suitable fitting could only be achieved by the anisotropic $XXZ$-type Hamiltonian, in which the exchange interaction for the out-of-plane component is smaller than that for the in-plane one by a ratio $\alpha =J_z/J_x=0.6$. Moreover, the absence of spin-orbit exciton around 30 meV indicates that Co${}^{2+}$ ions in CoPS${}_3$ have a $S=3/2$ state rather than a spin-orbital entangled $J_\rm{eff}=1/2$ ground state. Our result directly shows that CoPS${}_3$ is an experimental realization of the $XXZ$ model with a honeycomb lattice in 2D vdW magnets.

arXiv comment17 pages, 5 figures

References in corpus (26)

• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Discovery of intrinsic ferromagnetism in 2D van der Waals crystals
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Ising-Type Magnetic Ordering in Atomically Thin FePS3
• Linear spin wave theory for single-Q incommensurate magnetic structures
• Crystal and Magnetic Structures in Layered, Transition Metal Dihalides and Trihalides
• Suppression of magnetic ordering in XXZ-type antiferromagnetic monolayer NiPS3
• Electronic and magnetic properties of single-layer MPX${}_3$ metal phosphorous trichalcogenides
• 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
• An investigation of the quantum $J_1-J_2-J_3$ model on the honeycomb lattice
• Kitaev-Heisenberg Hamiltonian for High-Spin $d^7$ Mott Insulators
• Charge-spin correlation in van der Waals antiferromagenet NiPS3
• Antiferromagnetic ordering in van der Waals two-dimensional magnetic material MnPS3 probed by Raman spectroscopy
• Viewpoint: Opportunities and challenges of two-dimensional magnetic van der Waals materials: magnetic graphene?
• The magnetic properties and structure of the quasi-two-dimensional antiferromagnet CoPS${}_3$
• The magnetic exchange parameters and anisotropy of the quasi-two dimensional antiferromagnet NiPS${}_3$
• Bulk properties of van-der-Waals hard ferromagnet VI3
• Dirac magnons in a honeycomb lattice quantum XY magnet CoTiO3
• Tunneling transport of mono- and few-layers magnetic van der Waals MnPS${}_3$
• Accessing new magnetic regimes by tuning the ligand spin-orbit coupling in van der Waals magnets
• Single-ion properties of the $S_{eff}$ = 1/2 XY antiferromagnetic pyrochlores, Na$A^{\prime }$Co${}_2$F${}_7$ ($A^{\prime }=$ Ca${}^{2+}$, Sr${}^{2+}$)
• Unusual superexchange pathways in a Ni triangular lattice of NiGa${}_2$S${}_4$ with negative charge-transfer energy
• Molecular spin-orbit excitations in the J_eff = 1/2 frustrated spinel GeCo${}_2$O${}_4$
• Spin-orbit transitions in $\alpha$ and $\gamma$-CoV${}_2$O${}_6$
• Ordered magnetism in the intrinsically decorated $j{}_{\mathrm{eff}}$ = $\frac{1}{2}$ $\alpha$-CoV${}_3$O${}_8$

Cited by in corpus (22)

• Antiferromagnetic Kitaev interaction in $J_\rm{eff}=1/2$ cobalt honeycomb materials Na${}_3$Co${}_2$SbO${}_6$ and Na${}_2$Co${}_2$TeO${}_6$
• High-entropy van der Waals materials formed from mixed metal dichalcogenides, halides and phosphorus trisulfides
• Controlling magnetic exchange and anisotropy by non-magnetic ligand substitution in layered MPX3 (M = Ni, Mn; X = S, Se)
• Excitations in the ordered and paramagnetic states of honeycomb magnet Na2Co2TeO6
• Highly sensitive spin-flop transition in antiferromagnetic van-der Waals material MPS3 (M = Ni and Mn)
• Magnetic exchange interactions in the van der Waals layered antiferromagnet MnPSe3
• Spin-orbital entangled state and realization of Kitaev physics in 3d cobalt compounds: a progress report
• Probing quasi-long-range ordering by magnetostriction in monolayer CoPS3
• High entropy van der Waals materials (Review article)
• Bond-dependent anisotropy and magnon decay in cobalt-based Kitaev triangular antiferromagnet
• Spin wave Hamiltonian and anomalous scattering in NiPS${}_3$
• Ultrafast laser-induced spin-lattice dynamics in the van der Waals antiferromagnet CoPS3
• Spin wave spectra of single crystal CoPS${}_3$
• Spin Waves and Dirac Magnons in a Honeycomb Lattice Zig-zag Antiferromagnet BaNi2(AsO4)2
• Active orbital degree of freedom and potential spin-orbit-entangled moments in Kitaev magnet candidate BaCo${}_2$(AsO${}_4$)${}_2$
• Study of Staggered Magnetization in the Spin-$S$ Square-Lattice Heisenberg Model Using Spiral Boundary Conditions
• Long-range order in the XY model on the honeycomb lattice
• Spin and lattice dynamics of a van der Waals antiferromagnet MnPSe${}_3$
• Emergence of Meron Kekulé lattices in twisted Néel antiferromagnets
• Thermally-induced mimicry of quantum cluster excitations and implications for the magnetic transition in FePSe${}_3$
• Long-range magnetic order with disordered spin orientations in a high-entropy antiferromagnet
• Understanding the magnetic interactions of the zig-zag honeycomb lattice: Application to $\alpha$-RuCl${}_3$