Second Harmonic Generation of MoSi2N4 Layer

TL;DR

This paper investigates the second harmonic generation (SHG) properties of MoSi2N4 and its derivatives, revealing how structural differences and strain influence SHG responses, with implications for nonlinear optics and optoelectronics.

Contribution

It introduces the use of SHG as a tool to identify structural details in MoSi2N4 and explores strain effects on SHG in derivatives, including anomalous responses in MoSi2P4 and MoGe2P4.

Findings

SHG intensity varies with structural details

Strain affects SHG response significantly

Anomalous SHG responses observed in MoSi2P4 and MoGe2P4

Abstract

The recently discovered two-dimensional (2D) layered semiconductor MoSi2N4 has aroused great interest due to its unique 2D material characteristics. In this Letter, we found that differences in the structural details for MoSi2N4 may lead to differences in the intensity of second harmonic generation (SHG) and its response to strain. Accordingly, SHG can be used as a simple technique to identify the structural details of this system. We further calculated the SHG effects of MoSi2N4 derivatives and investigated their strain-regulation mechanism, especially including the anomalous SHG responses under strain for MoSi2P4 and MoGe2P4, differing from other known 2D materials. The studies may have forward-looking significance for the research of nonlinear optics and optoelectronics in this novel 2D material system.