Anomalous conductivity tensor in the Dirac semimetal Na_3Bi

TL;DR

This paper investigates the anomalous magnetotransport properties of the Dirac semimetal Na_3Bi, revealing robust anomalies in conductivity and resistivity tensors under high magnetic fields, indicating unusual sensitivity of transport lifetime to magnetic fields.

Contribution

It reports the first detailed experimental observation of anomalous conductivity tensor behavior in Na_3Bi, highlighting its sensitivity to magnetic fields and comparing it with Cd3As2.

Findings

Resistivity ρ_xx is linear in B up to 35 T

Hall angle exhibits an unusual step-like profile

Conductivities σ_xx and σ_xy follow power-law dependences at high B

Abstract

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 $\rho_{xx}$ is B-linear up to 35 T, while the Hall angle exhibits an unusual profile approaching a step-function. The conductivities $\sigma_{xx}$ and $\sigma_{xy}$ 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. Comparison with Cd3As2 is made.