Achieving Large and Anisotropic Spinon Thermal Transport in Textured Spin-Chain Compound Ca₂CuO₃

Spinons, as spin excitations in antiferromagnetic Heisenberg spin-chain systems, are crucial for exploring novel physical phenomena and practical applications in thermal management. However, current research is limited to single crystals, and research on polycrystals is lacking, which affects its widespread application. This work reports large and anisotropic spinon thermal transport in highly textured spin chain compound Ca₂CuO₃, fabricated by pressing nanosheets using the developed solvent-cast cold pressing (SCCP) method. The SCCP method effectively aligned the spin chains and inhibited spinon thermal transport in the plane parallel to the press direction, as confirmed by X-ray diffraction and Raman spectroscopy. As a result, a high thermal conductivity (κ) for polycrystalline magnetic insulators, approximately 12 W/m K near 300 K, with an aspect ratio of κ approaching 4.5. Compared to the conventional cold-pressed sample, κ_s extracted from the textured pellet is increased by about 50%. Furthermore, the spinon thermal transport processes, including spinon-defect and spinon-phonon scattering, were analyzed using a kinetic model for 1D spinon transport. These results provide useful insights into enhancing spinon thermal transport in 2D magnetic structures, presenting a promising approach for developing advanced thermal management devices.