AI Article Synopsis
- Van der Waals (vdW) stacking of 2D materials like bilayer MoS and monolayer graphene can create unique structures that exhibit second-harmonic generation (SHG).
- The interlayer charge transfer and uneven charge distribution in bilayer MoS are key factors in breaking centrosymmetry, allowing for enhanced SHG properties, confirmed by various scientific methods.
- The observed SHG strength in the 2LM/1LG heterostructure is comparable to that of monolayer MoS, indicating potential for using SHG spectroscopy to study interlayer interactions in these materials.
Article Abstract
Van der Waals (vdW) stacking of two-dimensional (2D) materials to create artificial structures has enabled remarkable discoveries and novel properties in fundamental physics. Here, we report that vdW stacking of centrosymmetric 2D materials, e.g., bilayer MoS (2LM) and monolayer graphene (1LG), could support remarkable second-harmonic generation (SHG). The required centrosymmetry breaking for second-order hyperpolarizability arises from the interlayer charge transfer between 2LM and 1LG and the imbalanced charge distribution in 2LM, which are verified by first-principles calculations, Raman spectroscopy, and polarization-resolved SHG. The strength of SHG from 2LM/1LG is of the same order of magnitude as that from the monolayer MoS, which is well recognized with strong second-order nonlinearity. The emergent SHG reveals that the interlayer charge transfer can effectively modify the symmetry and nonlinear optical properties of 2D heterostructures. It also indicates the great opportunity of SHG spectroscopy for characterizing interlayer coupling in vdW heterostructures.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10017043 | PMC |
| http://dx.doi.org/10.1126/sciadv.adf4571 | DOI Listing |
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