【报告题目】Axion physics in condensed matter systems
【报告人】栗宇航 博士 加州大学河滨分校
【时间】2023年11月8日(周三)下午14:30-15:30
【主办方】浙江光电子研究院 浙江师范大学
【线下地点】光电子研究院302报告厅(北山路285号)
【报告摘要】Axion insulator possesses a quantized axion field \theta=\pi 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.
References:
[1] Yu-Hang Li and Ran Cheng, Physical Review Research 4, L022067(2022)
[2] Yu-Hang Li, Hua Jiang and X. C. Xie, to appear
[3] Shuai Li, Ming Gong, Yu-Hang Li, Hua Jiang and X. C. Xie, to appear
【报告人简介】栗宇航，1990年9月生，2013年本科毕业于四川大学物理学基地班，2018年博士毕业于北京大学量子材料科学中心，并荣获北京大学优秀毕业生，导师谢心澄院士。2019年1月至今在加州大学河滨分校从事博士后研究工作。目前主要从事磁性材料和拓扑材料的理论研究。近年来以第一作者身份发表SCI论文10篇，包括Phys. Rev. Lett. 1篇、npj Quantum Materials 1篇、Phys. Rev. Research 2篇、Phys. Rev. B 4篇。