Physical orders have been serving as the heart of condensed matter physics research and various applications. Toggling different order parameters via contactless light field is attracting tremendous attention, which is invasive and is less-susceptible to lattice damage. In this talk, we try to discuss the relationship between nonlinear optical response and antiferromagnetic orders in various material systems. By establishing optical response functions and magnetic group symmetry analysis, we point out that the direction of Néel vector can significantly change the magnetic symmetry of the system, thereby affecting the generation rule of bulk photovoltaic current. Furthermore, we propose a scheme to reorient the Néel vector by optical approaches, and explore the differences in symmetry between AFM systems and altermagnetic materials. Through scrutinizing different symmetries, we suggest that linearly polarized light could switch the Néel vector in AFMs, but it produces spin canting in general AMs, giving contrasting spintronics behaviors.

Jian Zhou, Professor at School of Materials Science and Engineering, Xi'an Jiaotong University. Zhou received his Bc.S. (2008) and Ph.D. (2013) at Peking University in Theoretical Mechanics, followed by Postdoctoral Association position at Virginia Commonwealth University and Massachusetts Institute of Technology (2013-2018). His current research interests mainly focuses on first-principles calculations of nonlinear optics of condensed matter materials, photoinduced material structures, and topological phase transitions. So far, he has co-authored over 100 papers in PNAS, PRL, JACS, Nano Letters, etc. These papers have been cited ~ 7,000 times, with an h-index of 37, and was selected as "Elsevier Chinese Highly Cited Scholar" and "World’s Top 2% Scientists". These works are sponsored by grants from the Chinese Young-Talent Program and National Natural Science Foundation of China.