CrPS4 exhibits a second harmonic generation effect induced by a single-layer ferromagnetic order. Left: Optical images of single-layer CrPS4; Right: Characterization by atomic force microscopy. Credit: Hou De
A research team led by Professor Sheng Zhigao from the Hefei Institutes of Physical Sciences of the Chinese Academy of Sciences has, for the first time, observed the strong nonlinear magnetic second harmonic generation (MSHG) induced by ferromagnetic order in monolayer CrPS4with the help of stable and high magnetic field installation.
The results were published in Advanced optical materials.
Second harmonic generation (SHG) is a nonlinear optical effect sensitive to symmetry breaking in materials. SHG was first observed in symmetry-broken crystals (i-type) and also occurs in magnetic systems (c-type), although it is much weaker. This limits its use in optical devices.
Two-dimensional van der Waals magnetic materials, which have attracted attention for their unique properties, still exhibit unexplored nonlinear optical properties, especially the link between SHG and magnetic order, which limits their potential in optoelectronics.
In this study, Sheng’s team extensively investigated the SHG effects related to magnetic ordering in the two-dimensional antiferromagnetic material CrPS.4They found that in bulk and uniformly layered CrPS4antiferromagnetic ordering did not produce any c-type SHG effect, whereas a substantial c-type SHG effect induced by monolayer ferromagnetic ordering was observed in odd-layer CrPS4.
This is the first observation of ferromagnetic order-induced c-type SHG effects in a 2D magnet under the electric-dipole approximation, resulting from the double breaking of spatial and time inversion symmetries.
More importantly, the research team found that the c-type SHG induced by ferromagnetic order has a signal intensity comparable to that of the i-type SHG, which results from the breaking of crystal structural symmetry. This is extremely rare among all known magnetic materials.
“Our discovery revealed a new mechanism for SHG in two-dimensional magnetic materials,” said Hou De, first author of the paper, “and greatly enriched the category of SHG generated by magnetic order.”
More information:
De Hou et al., Extraordinary generation of second magnetic harmonic in monolayer CrPS4, Advanced optical materials (2024). DOI: 10.1002/adom.202400943
Provided by Chinese Academy of Sciences
Quote:A strong magnetic second harmonic generation effect discovered in a two-dimensional CrPS₄ monolayer (2024, September 10) retrieved September 10, 2024 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without written permission. The content is provided for informational purposes only.
