Spiral spin-liquid on a honeycomb lattice

TL;DR

This paper reports the experimental observation of a spiral spin-liquid state in the 2D honeycomb magnet FeCl₃ using neutron scattering, revealing a continuous ring of scattering indicative of emergent U(1) symmetry and opening avenues for studying fracton physics.

Contribution

First experimental realization of a spiral spin-liquid in a 2D honeycomb magnet, demonstrating emergent U(1) symmetry and potential for fracton physics studies.

Findings

Observation of a continuous ring of scattering in neutron data

Evidence of emergent U(1) symmetry in momentum space

FeCl₃ as a platform for 2D spiral spin-liquid physics

Abstract

Spiral spin-liquids are correlated paramagnetic states with degenerate propagation vectors forming a continuous ring or surface in reciprocal space. On the honeycomb lattice, spiral spin-liquids present a novel route to realize emergent fracton excitations, quantum spin liquids, and topological spin textures, yet experimental realizations remain elusive. Here, using neutron scattering, we show that a spiral spin-liquid is realized in the van der Waals honeycomb magnet FeCl$_3$. A continuous ring of scattering is directly observed, which indicates the emergence of an approximate U(1) symmetry in momentum space. Our work demonstrates that spiral spin-liquids can be achieved in two-dimensional systems and provides a promising platform to study the fracton physics in spiral spin-liquids.