Abstract

　　The anomalous Hall effect (AHE), conventionally associated with time-reversal symmetry breaking in ferromagnetic materials, has recently been observed in nonmagnetic topological materials, raising questions about its origin. We unravel the unconventional Hall response in the nonmagnetic Dirac material ZrTe₅, known for its massive Dirac bands and unique electronic and transport properties. Using the Kubo-Streda formula within the Landau level framework, we explore the interplay of quantum effects induced by the magnetic field (B) and disorder across the semiclassical and quantum regimes. In the semiclassical regime, the Hall resistivity remains linear in the magnetic field, but the Hall coefficient will be renormalized by the quantum geometric effects and electron-hole coherence, especially at low carrier densities where the disorder scattering dominates. In quantum limit, the Hall conductivity exhibits an unsaturating 1/B scaling. As a result, the transverse conductivity dominates transport in the ultra-quantum limit, and the Hall resistivity crosses over from B to 1/B dependence as the system transitions from the semiclassical regime to the quantum limit. This work elucidates the mechanisms underlying the unconventional Hall effect in ZrTe₅ and provides insights into the AHE in other nonmagnetic Dirac materials as well.

Biosketch:

　　Dr. Bo Fu earned his Ph.D. in Condensed Matter Physics from the University of Science and Technology of China in 2017. Following his doctoral studies, he pursued postdoctoral research at The University of Hong Kong. In 2023, he joined Great Bay University as an assistant professor in the School of Science. His research investigates emergent quantum phenomena driven by the interplay of electromagnetic fields, topology, and disorder, with a focus on magneto-transport in Dirac systems, higher-order topological states and unconventional superconductors, and quantum criticality in disordered systems.