High thermal conductivity mediated by spin excitations has been recently observed in several quantum materials with unique low-dimensional crystal structures. However, the thermal transport mechanisms of spin excitations are not well understood. ECE Professor Xi Chen and his team have reported the synthesis and thermal transport measurements of spin ladder Sr14Cu24O41 microstructures for the first time. A four-probe thermal conductivity measurement revealed appreciable spin-mediated thermal transport in the microstructures. Further studies suggested that the spin-mediated thermal transport is mainly limited by defect scattering and can be enhanced upon high-temperature annealing. These results help to build the foundation for future heterogeneous integration of magnetic microstructures in microscale devices for the transport of energy and quantum information. The results have been published in Advanced Functional Materials (link to the paper). Youming Xu in Chen’s group is the coauthor of this paper.
Besides microstructures, Professor Chen is actively investigating the thermal transport in bulk single crystals of quantum materials. He has established the capability to grow high-quality single crystals using floating zone technique at UCR. With this technique, he has previously grown large-size crystals of a spin chain compound and discovered weak coupling between spin excitations and lattice vibrations (link to the paper).