题 目： Axion physics in condensed matter systems
报 告 人：栗宇航 博士 University of California, Riverside
时 间： 2023年11月13日（星期一) 上午 08：30
地 点： 虎溪校区理科楼LE201
报告摘要：Axion insulator possesses a quantized axion field θ=π protected by combined lattice and time-reversal symmetry, holding great potentials for device applications in layertronics and quantum computing. Although some experiments hinted that MnBi2Te4 is a possible candidate as theoretical prediction, the direct evidence for this exotic state remains elusive. We propose a MnBi2Te4 tunnel junction, in which the axion insulator phase can be unambiguously determined by the quantized current induced by a harmonic magnetic field. On the other hand, we extend this axion insulator to the high spin case and thus propose a high spin axion insulator defined on spin-s representation. Moreover, when both time-reversal and space inversion symmetries are absent, a new kind of materials termed dynamic axion insulator with a temporal dependent axion field can emerge in the presence of antiferromagnetic resonance. We show that a dynamic axion insulator Josephson junction exhibits a striking doubled Shapiro steps in the presence of a dc bias and a static magnetic field, which furnishes a hallmark for the dynamic axion insulator. Our work enriches the understanding of axion insulator in condensed matter systems, paving the way for future device applications.
. Yu-Hang Li and Ran Cheng, Physical Review Research 4, L022067(2022)
. Yu-Hang Li, Hua Jiang and X. C. Xie, to appear
. Shuai Li, Ming Gong, Yu-Hang Li, Hua Jiang and X. C. Xie, to appear
报告人介绍：Dr Yuhang Li is currently a postdoctoral scholar at the University of California, Riverside. He received his bachelor degree from Sichuan University in 2013, and earned his Ph.D from International Center for Quantum Materials at Peking univer-sity in 2018. His research interests focus on quantum transport, spintronics, and magnetism.