Axion physics in condensed matter systems

Axion is a hypothetical elementary particle from high-energy physics, which was initially postulated to solve the strong charge-parity problem in QCD. It is also considered to be a possible component of dark matter in the universe. However, its existence has yet to be confirmed in nature. Intriguingly, axion emerges in the effective field theory description of topological insulators and has attracted extensive recent attention in condensed matter physics. In this seminar, I will first give a brief introduction to axion physics in condensed matter systems, including topological insulators and Weyl-charge-density-wave systems. Then I will talk about some of our works on both static and dynamic axion insulators in antiferromagnetic topological phases of Mn1Bi2Te4-based Van der Waals heterostructures.