Abstract: The quantum Hall effect is usually observed in 2D systems. We show that the Fermi arcs can give rise to a distinctive 3D quantum Hall effect in topological semimetals. Because of the topological constraint, the Fermi arc at a single surface has an open Fermi surface, which cannot host the quantum Hall effect. Via a “wormhole” tunneling assisted by the Weyl nodes, the Fermi arcs at opposite surfaces can form a complete Fermi loop and support the quantum Hall effect. The edge states of the Fermi arcs show a unique 3D distribution, giving an example of (d − 2)-dimensional boundary states. This is distinctly different from the surface-state quantum Hall effect from a single surface of topological insulator. As the Fermi energy sweeps through the Weyl nodes, the sheet Hall conductivity evolves from the 1/B dependence to quantized plateaus at the Weyl nodes. This behavior can be realized by tuning gate voltages in a slab of topological semimetal, such as the TaAs family, Cd3As2, or Na3Bi. This work will be instructive not only for searching transport signatures of the Fermi arcs but also for exploring novel electron gases in other topological phases of matter.

 

 

Reference:

[1] C. M. Wang, H. P. Sun, H. Z. Lu*, and X. C. Xie, PRL 109, 136806 (2017).

 

Bio: Haizhou Lu obtained his Ph.D. in Physics from Tsinghua University, Beijing, in 2007. From 2007 to 2015, he worked for the University of Hong Kong first as a postdoc then research assistant professor. He is now an associate professor at Southern University of Science and Technology in Shenzhen. His research interest is the quantum transport in topological states of matter. He has published over 50 articles in physics journals, including 10 in PRL, 1 in Nature Physics, and 3 in Nature Communications, with a citation over 2000 and h-index of 25.