报告题目：Light-Induced Ultrafast Control of Polarization and Magnetization in Semiconductors

报 告 人：Xiangzhu Zhou

报告时间：2026年7月21日10：00

报告地点：物理楼W105会议室

内容摘要：Ultrafast optical control of ordered states offers a route toward high-speed functional materials. However, in ferroelectrics optical switching often relies on interlayer sliding or structural distortions, which can limit the speed of polarization control. In magnetism, optical control is commonly associated with angular-momentum transfer mechanisms using circularly polarized light, whereas inducing magnetization with linearly polarized light is consider to be rare. Here, I will discuss how photoexcited carriers can transiently control polarization and magnetization in semiconductors, combining constrained density-functional theory (cDFT), many-body real-time simulations, and high-throughput screening.First, we demonstrate that rhombohedrally stacked transition-metal dichalcogenide (TMD) bilayers can exhibit a transient reversal of their out-of-plane polarization through layer-selective charge redistribution, without interlayer sliding. This electronically driven reversal occurs at moderate photoexcited carrier density and develops within a few hundred femtoseconds, much faster than structural sliding.Second, we present a high-throughput first-principles search for light-induced magnetization in nonmagnetic semiconductors excited by linearly polarized pulses. The screening identifies a broad class of candidate materials in which photoexcited carriers can trigger exchange-driven spin polarization, with the magnitude and magnetic order governed by local coordination motifs and band-edge orbital characters.

In conclusion, these results identify a distinct nonequilibrium pathway for transiently tuning ferroic properties in semiconductors, with the resulting response rooted in the character of the photoexcited band-edge states.

报告人简介：Xiangzhu Zhou obtained his B.S. from Xi’an Jiaotong University, M.Sc. and Ph.D. degree from ETH Zurich and the Technical University of Munich respectively. He is currently a Postdoctoral Researcher at the University of Trento. His research focuses on first-principles and many-body simulations of light-induced phenomena in quantum materials.