Title: Quantum Magnetoconductivity of Topological Semimetals in High Magnetic Fields

Lecturer: Shun-Qing Shen, Department of Physics, The University  of Hong Kong

Time: June 2（Tuesday）15:00

Place：Room 520, New Building

Abstract: Weyl semimetals are three-dimensional topological states of matter, in a sense that they host paired monopole and anti-monopole of Berry curvature in momentum space, leading to the chiral anomaly. Here, we study the quantum magnetoconductivity of Weyl and Dirac semimetals in the diffusive regime. In the presence of a strong magnetic field along the direction connecting two Weyl nodes, it is found that the conductivity along the field is determined by the Fermi velocity. The conductivity is independent of the magnetic field in the undoped case that the Fermi level crosses the Weyl nodes. The magnetoconductivity is negative in the electron-doped regime while it is positive in the hole-doped regime. Meanwhile the conductivity normal to the field is negligibly weak, and its magnetoconductivity is positive. The high anisotropy of the magnetoconductivity is attributed to the chiral anomaly in the transport of Weyl semimetals. The magnetoconductivity of Dirac semimetals is always negative in strong fields.