Magnetic and Light Dance: Research discovers that non-regenerative second harmonic generation disappears in 2D materials

The research group recently discovered the disappearance of non-re-ricoral second harmonic generation (SHG) of MNPSE₃ when integrated into a two-dimensional (2D) antiferromagnetic MNPSE/graphene heterojunction.

This study, published in Nano Letters, highlights the role of interface magnon plasmon coupling in this phenomenon.

2d van der waals magnetic/nonmagnetic heterojunctions are of great promise for spintronic devices. Achieving these functions depends on the important factor: the interfacial proximity effect. However, detecting the proximity effects of 2D antiferromagnetic/nonmagnetic heterojunctions presents considerable challenges due to the size and weak signals associated with these structures.

In this study, the team used a homemade SHG system to observe that the inphasic SHG of mnpse ₃ disappeared when in contact with graphene, as opposed to the antiferromagnetic mnpse ₃ layer alone. This change indicates the presence of interfacial binding interactions or proximity effects.

To further explore this effect, the researchers incorporated a hexagonal boron nitride (H-BN) layer between MNPSE₃ and graphene to separate interfacial interactions. Their experiments revealed that interfacial bonds were extended to long distances (>40 nm), significantly exceeding the typical range of several nanometers that are normally observed in proximity effects.

Furthermore, the team found that this bond strength weakens as the band gap of the underlying material increases, providing a way to adjust the nonlinear SHG response. By symmetry analysis, first principle calculations, and comparisons with previous studies, the researchers concluded that the disappearance of the non-repetitive SHG signal was due to the bonding of the surface plasmon of graphene and the magnon of Mnpse₃. .

“This discovery paves the way for developing multifunctional, tunable, 2D layer nonlinear optical devices that manipulate the nonlinear optical properties of 2D heterojunctions,” says Professor Sheng Zhigao.

The study was led by Professor Sheng of the HEFEI Institute of Physical Sciences at the Chinese Academy of Sciences.