Thermal Conductivity in triangular spin supersolid K₂Co(SeO₃)₂

Spin supersolid describes the quantum state where the translational symmetry and U(1) symmetry are simultaneously broken, leading it to share traits of both superfluid and solid. Recently, there have been neutron scattering reports on triangular spin supersolid K2Co(SeO3)2 , showing the observation of Goldstone mode alone with a gapped pseudo-goldstone mode at low temperature that are sensitive to magnetic field [1][2]. We present field-dependent thermal conductivity kxx at low temperatures, where two modes of sharp peaks are observed, possibly corresponding to the Goldstone modes. The behavior of the peaks are examined at different temperatures, and the phases of KCSO are analyzed with respect to the behavior of kxx at different fields and temperatures.

[1] T. Chen et al., arXiv:2402.15869 [cond-mat.str-el] (2024).

[2] Zhu, M., Chinellato, L.M., Romerio, V. et al. Wannier states and spin supersolid physics in the triangular antiferromagnet K2Co(SeO3)2. npj Quantum Mater. 10, 74 (2025). https://doi.org/10.1038/s41535-025-00791-2