Giant chiral magnetoelectric oscillations in a van der Waals multiferroic
Frank Y. Gao, Xinyue Peng, Xinle Cheng, Emil Vinas Bostrom, Dong Seob Kim, Ravish K. Jain, Deepak Vishnu, Kalaivanan Raju, Raman Sankar, Shang-Fan Lee, Michael A. Sentef, Takashi Kurumaji, Xiaoqin Li, Peizhe Tang, Angel Rubio*, Edoardo Baldini*. “Giant chiral magnetoelectric oscillations in a van der Waals multiferroic”. Nature 632, 273–279 (2024).
In collaboration with Prof. Edoardo Baldini from the University of Texas at Austin, Dr. Raman Sankar and Dr. Shang-Fan Lee have published a research article in Nature. Utilizing high-quality samples of the helical van der Waals multiferroics NiI2, the team conducted advanced optical measurements that successfully identified an enantiopure domain within the crystal. Precision measurements of the dynamical magnetoelectric coupling, achieved through ultrafast optical probes, revealed a giant natural optical activity. This chiral property is characterized by quadrature modulations between the electric polarization and magnetization components in the terahertz frequency regime. The observed chiral couplings stem from the interplay between the material’s non-collinear spin texture and relativistic spin–orbit interactions, leading to significant enhancements beyond those typically mediated by lattice effects.
Left panel: The spin-spiral order depicted on the (001) plane with the in-plane component of the propagation vector qin, and electric polarization P along y, parallel to the C2 axis. Also shown is the x, y, z coordinate system, where y ∥ [010] and z ∥ [001].
Right panel: Spin precessions of EMo and EMe, shown alongside the calculated polarization and magnetization modulations for each mode.
Journal Links: https://www.nature.com/articles/s41586-024-07678-5