Magnetic-field control of fundamental optical properties is a crucial challenge in the engineering of multifunctional microdevices. Van der Waals (vdW) magnets retaining a magnetic order even in atomically thin layers, offer a promising platform for hosting exotic magneto-optical functionalities owing to their strong spin-charge coupling. Here, we demonstrate that a giant optical anisotropy can be controlled by magnetic fields in the vdW magnet FePS3. The giant linear dichroism (∼11%), observed below TN∼120 K, is nearly fully suppressed in a wide energy range from 1.6 to 2.0 eV, following the collapse of the zigzag magnetic order above 40 T. This remarkable phenomenon can be explained as a result of symmetry changes due to the spin order, enabling minority electrons of Fe2+ to hop in a honeycomb lattice. The modification of spin-order symmetry by external fields provides a novel route for controllable anisotropic optical micro-devices.
@article{arxiv.2405.10326,
title = {Giant Linear Dichroism Controlled by Magnetic Field in FePS$_3$},
author = {Xu-Guang Zhou and Zhuo Yang and Youjin Lee and Jaena Park and Yoshimitsu Kohama and Koichi Kindo and Yasuhiro H. Matsuda and Je-Geun Park and Oleg Janson and Atsuhiko Miyata},
journal= {arXiv preprint arXiv:2405.10326},
year = {2024}
}