Antiferromagnetic Topological Insulators

  • Event Date: 2019-01-08
  • AMO/QIS/CMT
  • Speaker: Dr. Peng-Jen Chen (Academia Sinica)  /  Host: Prof. Germar Hoffmann (NTHU)
    Place: Lecture room A of NCTS, 4F, 3rd General Building, Nat'l Tsing Hua Univ.

The topological insulators (TIs) are emerging quantum matters that exhibit intriguing properties on surfaces. It is well-known that the nontrivial topology, characterized by Z2 invariant, is protected by the time-reversal symmetry (TRS). That is to say, breaking of the TRS simultanesouly destroys the Z2 topology. However, it is proposed that materials with specific antiferromagnetic configurations can still be classified into Z2 topology due to the presence of a new protecting symmetry [1]. Since the theoretical proposal, no materials have been found to reveal this kind of topological phase. In this talk, I will demonstrate that pressurized SmB6, which is A-type antiferromagnetic, is a candidate for such antiferromagnetic Z2 topological phase [2]. Possible applications in spintronics will be briefly discussed. Very recently, we have found another G-type antiferromagnetic semiconductor that shows the antiferromagnetic Z2 topological phase at ambient condition. Some preliminary results will be discussed.