Suppressed Nonreciprocal Second-Harmonic Generation of Antiferromagnet MnPSe in the MnPSe/Graphene Heterostructure Due to Interfacial Magnon-Plasmon Coupling.

Interfacial coupling is one of the keys to manipulating magnetic/nonmagnetic two-dimensional (2D) heterostructures for novel functionalities. The MnPSe/graphene heterostructure is a prospective platform for quantum information and metrology. However, how graphene affects MnPSe through interfacial coupling is still poorly understood. Herein, second-harmonic generation (SHG) of antiferromagnet MnPSe in the MnPSe/graphene heterostructure is revealed. Surprisingly, it was found that below , nonreciprocal or c-type SHG of MnPSe disappeared when interfacing with the graphene, suggesting the existence of interfacial couplings and/or interactions. Most interestingly, different from the short-range interfacial proximity interaction, this interfacial interaction could be contactless and long-range and varied from 2D metallic/semiconducting to insulating underlayers. Interfacial magnon-plasmon coupling probably played an important role in suppressing the c-type SHG signals of MnPSe in the MnPSe/graphene heterostructure. This study will improve our understanding of the manipulation of nonlinear optical properties in 2D heterostructures.