Nematic spin liquid in a spin-1 pyrochlore magnet and its realization in $\mathrm{NaCaNi}_2\mathrm{F}_7$

Abstract

The search for spin liquids, magnetic phases which lie outside the Landau paradigm, remains one of the central challenges for modern condensed matter physics. For a long time, the prime candidates were thought to be spin-1/2 magnets, but recently examples have been identified in many spin-1 materials, including the pyrochlore NaCaNi$_2$F$_7$. Here we use numerical simulation to explore the spin liquid phases which arise in a minimal model of a spin-1 magnet on the pyrochlore lattice. We find this model supports seven distinct spin liquid phases, including one with nematic correlations. Through quantitative comparison with inelastic neutron scattering, we show that this nematic spin liquid provides a compelling scenario for NaCaNi$_2$F$_7$. These results suggest that the behaviour of spin liquids found in spin-1 pyrochlore magnets may be even richer than in materials with spin-1/2 moments.