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Magnetic Order-Induced Polarization Anomaly of Raman Scattering in 2D Magnet CrI3

Authors :
Hugen Yan
Takashi Taniguchi
Yuanzhen Chen
Chusheng Zhang
Mingyuan Huang
Bingbing Lyu
Qihang Liu
Jia-Wei Mei
Mengyuan Jia
Xinwei Wang
Xiaohua Wu
Minghui Wu
Shixuan Zhao
Li Huang
Le Wang
Kenji Watanabe
Yue Zhao
Yujun Zhang
Junyang Chen
Source :
Nano Letters. 20:729-734
Publication Year :
2019
Publisher :
American Chemical Society (ACS), 2019.

Abstract

The recent discovery of 2D magnets has revealed various intriguing phenomena due to the coupling between spin and other degree of freedoms (such as helical photoluminescence, nonreciprocal SHG). Previous research on the spin-phonon coupling effect mainly focuses on the renormalization of phonon frequency. Here we demonstrate that the Raman polarization selection rules of optical phonons can be greatly modified by the magnetic ordering in 2D magnet CrI$_3$. For monolayer samples, the dominant A$\rm_{1g}$ peak shows abnormally high intensity in the cross polarization channel at low temperature, which is forbidden by the selection rule based on the lattice symmetry. While for bilayer, this peak is absent in the cross polarization channel for the layered antiferromagnetic (AFM) state and reappears when it is tuned to the ferromagnetic (FM) state by an external magnetic field. Our findings shed light on exploring the emergent magneto-optical effects in 2D magnets.<br />Comment: 15 pages, 4 figures

Details

ISSN :
15306992 and 15306984
Volume :
20
Database :
OpenAIRE
Journal :
Nano Letters
Accession number :
edsair.doi.dedup.....829857e9271b11f6e95fb2b6bde59710