Data from: Quantum disordered ground state in the triangular-lattice magnet NaRuO2

It has long been hoped that spin liquid states might be observed in
materials that realize the triangular-lattice Hubbard model. However, weak
spin–orbit coupling and other small perturbations often induce
conventional spin freezing or magnetic ordering. Sufficiently strong
spin–orbit coupling, however, can renormalize the electronic wavefunction
and induce anisotropic exchange interactions that promote magnetic
frustration. Here we show that the cooperative interplay of spin–orbit
coupling and correlation effects in the triangular-lattice magnet NaRuO2
produces an inherently fluctuating magnetic ground state. Despite the
presence of a charge gap, we find that low-temperature spin excitations
generate a metal-like term in the specific heat and a continuum of
excitations in neutron scattering, reminiscent of spin liquid states
previously found in triangular-lattice organic magnets. Further cooling
produces a crossover into a different, highly disordered spin state whose
dynamic spin autocorrelation function reflects persistent fluctuations.
These findings establish NaRuO2 as a cousin to organic, Heisenberg spin
liquid compounds with a low-temperature crossover in quantum disorder.