Physics

Chiral anomaly

Geometric phase

Weyl semimetal

Mathematics

Magnetic field

Magnetoresistance

Hall effect

Semimetal

Band gap

Neutrino

Magnetometer

Berry connection and curvature

Curvature

Quantum Hall effect

Geometry

Condensed matter physics

Fermion

Dirac (video compression format)

Quantum mechanics

Landau quantization

Nature Physics

Research in topological matter has expanded to include the Dirac and Weyl semimetals1–10, which feature three-dimensional Dirac states protected by symmetry. Zirconium pentatelluride has been of recent interest as a potential Dirac or Weyl semimetal material. Here, we report the results of experiments performed by in situ three-dimensional double-axis rotation to extract the full 4π solid angular dependence of the transport properties. A clear anomalous Hall effect is detected in every sample studied, with no magnetic ordering observed in the system to the experimental sensitivity of torque magnetometry. Large anomalous Hall signals develop when the magnetic field is rotated in the plane of the stacked quasi-two-dimensional layers, with the values vanishing above about 60 K, where the negative longitudinal magnetoresistance also disappears. This suggests a close relation in their origins, which we attribute to the Berry curvature generated by the Weyl nodes. Magnetotransport measurements show that ZrTe5 exhibits an anomalous Hall effect without magnetic ordering, a signature of Berry curvature introduced by Weyl nodes. This indicates that ZrTe5 may be a Weyl semimetal, even though this was not predicted.

Anomalous Hall effect in ZrTe5