Non-linear Hall Effect in Three-dimensional Weyl and Dirac Semimetals

We experimentally investigate a non-linear Hall effect for three-dimensional WTe2 and Cd3As2 single crystals, representing Weyl and Dirac semimetals, respectively. We observe finite second-harmonic Hall voltage, which depends quadratically on the longitudinal current in zero magnetic field, as it has been predicted theoretically. We demonstrate that second-harmonic Hall voltage shows odd-type dependence on the direction of the magnetic field, which is a strong argument in favor of current-magnetization effects. In contrast, one order of magnitude higher thermopower signal is independent of the magnetic field direction. Thus, the magnetic field dependence allows to distinguish the non-linear Hall effect from a thermoelectric response.