Abstract
A central theme in condensed matter physics is to create and understand the exotic states of matter by incorporating magnetism into topological materials. One prime example is the quantum anomalous Hall (QAH) state. The QAH effect can be considered as a zero magnetic field manifestation of the integer quantum Hall effect, which carries spin-polarized dissipation-free chiral edge current. Therefore, the QAH effect may have a huge impact on future electronic and spintronic device applications for ultralow-power consumption. The many decades' quest for the experimental realization of the QAH phenomenon became a possibility in 2006 with the discovery of topological insulators (TIs). In 2013, the QAH effect was observed in thin films of Cr-doped TI for the first time [1]. Two years later in a near-ideal system, V-doped TI, contrary to the negative prediction from first-principle calculations, a high-precision QAH quantization with more robust magnetization and a perfectly dissipationless chiral current flow was demonstrated [2]. In this talk, I will introduce our route to the experimental realization of these QAH systems [1, 2]. I will also talk about our recent progress on magnetic TI multilayer heterostructures from the axion insulator physics [3] to the high Chern number QAH effect [4] and the QAH-superconductor hybrid devices about the absence of evidence for chiral Majorana excitations [5].
References
[1] Chang et al, Science 340, 167 (2013).
[2] Chang et al, Nat. Mater. 14, 473 (2015).
[3] Xiao et al, Phys. Rev. Lett. 120, 056801 (2018).
[4] Zhao et al, Nature 588, 419 (2020).
[5] Kayyalha et al, Science 367, 64 (2020).
Anyone interested is welcome to attend.