Anomalous conductivity tensor in the Dirac semimetal Na₃Bi

Na₃Bi is a Dirac semimetal with protected nodes that may be sensitive to the breaking of time-reversal invariance in a magnetic field B. We report experiments which reveal that both the conductivity and resistivity tensors exhibit robust anomalies in B. The resistivity φ_xx is B-linear up to 35 T, while the Hall angle exhibits an unusual profile approaching a step function. The conductivities σ_xx and σ_xy share identical power-law dependences at large B. We propose that these significant deviations from conventional transport result from an unusual sensitivity of the transport lifetime to B. The transport features are compared with those in Cd₃As₂.