Colloquium
Department of Physics, NCU
Topological material: Intrinsic ferromagnetic axion insulator
Prof. 張泰榕 (Tay-Rong Chang)
Department of Physics, National Cheng Kung University
Date 2021.09.28 (Tue)
Place S4-625
Time 14:00-16:00
In the past decade, the correlation between symmetry and topology have taken the central stage of modern physics. It has attracted intensive research interests in condensed matter physics and materials science since the discovery of various topological materials such as quantum spin Hall insulators, 3D topological insulators, and inversion-symmetry breaking Weyl semimetals. Despite tremendous progress, the majority of known topological materials are nonmagnetic while the novel magnetic topological materials have remains elusive. In this talk, I will introduce our recent prediction on an intrinsic ferromagnetic axion state in the new magnetic topological material MnBi8Te13 [1] and discuss the magnetic topological phase transition in the family compound MnBi4Te7 [2]. Our finding provides a superior material realization to explore zero-field QAH effect, quantized topological magnetoelectric effect, and associated phenomena.
[1] Chaowei Hu et al., Realization of an intrinsic ferromagnetic topological state in MnBi8Te13, Science Advances 6, eaba4275 (2020).
[2] Chaowei Hu et al., Tuning magnetism and band topology through antisite defects in Sb-doped MnBi4Te7, Phys. Rev. B 104, 054422 (2021).