报告题目：Nonlinear magneto-optical effect in 2D magnets

报告时间：2025年2月27日（周四）15:30

报告地点：鼓楼校区唐仲英楼 B501

报  告 人：Shiwei Wu（ Fudan University）

摘      要：

The magneto-optical effects are known as an indispensable tool for studying condensed matter physics in quantum materials. In the past, attention has been paid to the linear magneto-optical effects such as Faraday rotation, Kerr rotation, and magnetic circular dichroism. In this talk, I will introduce the nonlinear magneto-optical effect based on the optical second harmonic generation (SHG). Compared to the linear Faraday/Kerr rotations that are only sensitive to non-zero magnetization in ferromagnetic materials, the nonlinear magneto-optical effect is more versatile and particularly powerful for anti-ferromagnetic materials. In 2019, we found the layered anti-ferromagnetism in CrI₃ bilayer leads to a giant nonreciprocal magnetic SHG, three orders of magnitude larger than that in bulk magnetic crystals [Nature 572, 497 (2019)]. Here I will report our latest study to use the phase-resolved magnetic SHG to elucidate magnetic polymorphism in 2D magnetic semiconductor CrSBr and demonstrate how the magnetic polymorphs can be deterministically switched in an unprecedented layer-selective manner [Nature Materials 24, 226 (2025)].

报告人简介：

Dr Shiwei Wu is currently Xie Xide Chair Professor of Physics and the director of Key Laboratory of Micro and Nano Photonic Structures (MOE) at Fudan University. His research focuses on the optical microscopy and spectroscopy of low-dimensional materials, with the effort of developing the novel experimental methods to solve cutting-edge problems in condensed matter physics. He obtained his bachelor degree from Fudan University in 2001 and his PhD degree from University of California, Irvine in 2007. Before joining the department of physics at Fudan in 2011, he worked in the Molecular Foundry of Lawrence Berkeley National Laboratory as a postdoc fellow.