Colloquium: Hai-Zhou Lu

Title: 3D Quantum Hall Effect

Speaker: Hai-Zhou Lu

                Southern University of Science and Technology of China

Place: Room 201, Teaching Building 12

Time: Mar. 15th，Friday, 15:00-17:00

Abstract

The discoveries of the quantum Hall effect have led to three Nobel prizes and the booming field of topological states of quantum matter. So far, the quantum Hall effect is observed only in 2D systems. We show that the Fermi arcs can give rise to a distinctive quantum Hall effect in topological semimetals in three dimensions [1]. Topological semimetals are 3D topological states of matter, in which the energy bands touch at a finite number of Weyl nodes. They host topologically-protected surface states, known as the Fermi arcs. Via a “wormhole” tunnelling assisted by the Weyl nodes, the Fermi arcs at two opposite surfaces can form a single 2D electron gas and support a quantum Hall effect in three dimensions. Possible signatures of the 3D quantum Hall effect have been observed in several experiments on the topological Dirac semimetal Cd3As2 [2-5]. Our discovery of this 3D quantum Hall give an example of (d-2)-dimensional boundary states, a promising direction in topological states of quantum matter.

References:

[1] C. M. Wang, Hai-Peng Sun, Hai-Zhou Lu*, and X. C. Xie, Phys. Rev. Lett. 119, 136806 (2017).

[2] C. Zhang, F. X. Xiu, et al., Nature Comm. 8, 1272 (2017); Nature 565, 331 (2019).

[3] Uchida, et al., Nature Comm. 8, 2274 (2017).

[4] Schumann, Stemmer, et al., Phys. Rev. Lett. 120, 016801 (2018).

[5] Lin, Z. M. Liao, et al., Phys. Rev. Lett. 112, 036602 (2019)].

Short Biography

Haizhou Lu obtained his Ph.D. in Physics from Institute for Advanced Study, Tsinghua University, Beijing, in 2007. From 2007 to 2015, he was a Postdoc and then Research Assistant Professor at the University of Hong Kong. He is now a Professor of physics at Southern University of Science and Technology, Shenzhen. His research is on the quantum transport in topological states of matter. He has published over 70 articles in physics journals, including 13 in PRL, 1 in Nature Physics, 4 in Nature Communications, 2 in Nature, with a citation over 3000 and h-index of 28.

Welcome to attend!