Searching for exotic transport properties in new topological states of matter is an active topic. One of the most fascinating transport phenomena in recently discovered Weyl semimetals (WSMs) is the negative longitudinal magnetoresistivity (nLMR) in the presence of a magnetic field $B$ parallel to an electric field $E$ , which is arguably attributed to the chiral anomaly. Another predicted key effect closely related to the chiral anomaly and the nonzero Berry curvatures in WSMs is the planar Hall effect (PHE), which has not been identified so far. Here we carry out the planar Hall measurements on ${\mathrm{Cd}}_3{\mathrm{As}}_2$ nanoplates, and find that, accompanied by the large nLMR, a PHE with nonzero transverse voltage can be developed while tilting the in-plane magnetic field $\mathit{B}$ away from the electric field $\mathit{E}$. Further experiments reveal that both the PHE and the nLMR can be suppressed synchronously by increasing the temperature, but still visible at room temperature, indicating the same origin of these two effects. Our experiments indicate that PHE may provide another key transport evidence for topologically nontrivial electronic structures in topological materials.

• Received 18 August 2017
• Revised 17 December 2017

DOI:https://doi.org/10.1103/PhysRevB.98.161110