Impact of spin-entropy on the thermoelectric properties of a 2D magnet

Heat-to-charge conversion efficiency of thermoelectric materials is closely linked to the entropy per charge carrier. Thus, magnetic materials are promising building blocks for highly efficient energy harvesters, as their carrier entropy is boosted by a spin degree of freedom. In this work, we investigate how this spin entropy impacts heat-to-charge conversion in A-type antiferromagnet CrSBr. We perform simultaneous measurements of electrical conductance and thermocurrent while changing magnetic order using temperature and magnetic field as tuning parameters. We find a strong enhancement of the thermoelectric power factor around the Néel temperature. We further reveal that the power factor at low temperature can be increased by up to 600% upon applying a magnetic field. Our results demonstrate that the thermoelectric properties of 2D magnets can be optimized by exploiting the sizeable impact of spin entropy and confirm thermoelectric measurements as a sensitive tool to investigate subtle magnetic phase transitions in low-dimensional magnets.