Despite the exciting implications of the Kitaev spin-Hamiltonian, finding and
confirming the quantum spin liquid state has proven incredibly difficult.
Recently the applicability of the model has been expanded through the
development of a microscopic description of a spin-1 Kitaev interaction. Here
we explore a candidate spin-1 honeycomb system, KNiAsO4​ , which meets many
of the proposed criteria to generate such an interaction. Bulk measurements
reveal an antiferromagnetic transition at ∼ 19 K which is generally robust
to applied magnetic fields. Neutron diffraction measurements show magnetic
order with a k=(23​,0,0) ordering vector which results in
the well-known ``zig-zag" magnetic structure thought to be adjacent to the
spin-liquid ground state. Field dependent diffraction shows that while the
structure is robust, the field can tune the direction of the ordered moment.
Inelastic neutron scattering experiments show a well defined gapped spin-wave
spectrum with no evidence of the continuum expected for fractionalized
excitations. Modeling of the spin waves shows that the extended Kitaev
spin-Hamiltonians is generally necessary to model the spectra and reproduce the
observed magnetic order. First principles calculations suggest that the
substitution of Pd on the Ni sublattice may strengthen the Kitaev interactions
while simultaneously weakening the exchange interactions thus pushing
KNiAsO4​ closer to the spin-liquid ground state.Comment: 13 pages, 7 figure