On September 25, Nature Communications published online a research paper titled "Itinerant and topological excitations in a honeycomb spiral spin liquid candidate" by Professor Li Yuesheng's team at the National Pulsed High Magnetic Field Center. Our university is the primary completion unit. 

A spiral spin liquid refers to a system where, driven by spin frustration, the system fluctuates between a large number of degenerate spiral ground states, whose wavevectors form continuous contours or surfaces in reciprocal space. These spiral ground states are accompanied by exotic topological spin excitations, such as spin vortices and momentum vortices, and hold potential applications in spintronics, topologically protected quantum computing, and fractal gauge theories. However, the transport and topological properties of spiral spin liquids remain largely unexplored experimentally.

In previous studies, Li Yuesheng's team reported on the spin-7/2 frustrated honeycomb antiferromagnet material GdZnPO, demonstrating it as an ideal platform for studying the two-dimensional easy-plane frustrated honeycomb lattice spin model. Experiments indicated that the second-nearest-neighbor antiferromagnetic coupling dominates in this system, with J₂/|J₁| ~1.5, forming a spiral spin liquid contour with ground state degeneracy near the K{1/3,1/3} point [PRL 133, 236704 (2024)]. The spiral spin liquid model can well explain the giant magnetic specific heat observed below the critical field (~12 T) and the giant low-temperature magnetocaloric effect near the critical field [Adv. Sci. e10086 (2025)], indicating the presence of low-energy spin excitations with an extremely high density of states. Furthermore, the high-quality, structurally disorder-free GdZnPO single crystals are good insulators, providing an ideal platform for experimentally studying the thermal transport and topological properties of two-dimensional spiral spin liquids.

Ultra-low temperature thermal conductivity and specific heat of GdZnPO.

In this study, the team conducted comprehensive thermal transport measurements on high-quality, highly insulating GdZnPO single crystals. The experiments revealed an anomalously large low-temperature thermal conductivity in the low-temperature limit. This indicates that the low-energy spin excitations in the GdZnPO spiral spin liquid not only possess a high density of states but also exhibit strong itinerancy. Additionally, the observed thermal Hall effect further suggests that these low-energy spin excitations are highly likely to be topological. This work provides important experimental evidence for the itinerant and topological nature of low-energy spin excitations in the spiral spin liquid material GdZnPO.

Paper link: https://doi.org/10.1038/s41467-025-63620-x