Nonreciprocal nonlocal spin transport observed in Dirac semimetal Cd3As2 nanoplates

Nonreciprocal transport phenomena, such as current direction dependent resistance, have recently attracted substantial research interest due to the underlying physics and potential applications for high-performance rectifiers. Here we report the observation of nonreciprocal spin transport in Dirac semimetal Cd3As2 nanoplates under nonlocal configuration. Nonlocal spin voltage amplitude exhibits an anomalous nonreciprocity with respect to the direction of local bias current. It is found that the nonreciprocity is prominent in the region near current leads and becomes more significant upon increasing the bias current amplitude and tuning the Fermi level toward the Dirac point. This unusual nonreciprocity can be well understood by combining the charge current spreading and thermally induced spin polarization of topological surface states. Our results reveal the influence of thermal effect on the spin transport of topological surface states in nonlocal configuration, which should be valuable for thermal spintronics based on topological materials.