Nonlinear Optical Responses of Janus MoSSe/MoS<sub>2</sub> Heterobilayers Optimized by Stacking Order and Strain.
basic_science · Level V
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- Record sourced from PubMed, PMID 37643404.
- Also identified by DOI 10.1021/acsnano.3c04436.
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Abstract
Nonlinear optical responses in second harmonic generation (SHG) of van der Waals heterobilayers, Janus MoSSe/MoS<sub>2</sub>, are theoretically optimized as a function of strain and stacking order by adopting an exchange-correlation hybrid functional and a real-time approach in first-principles calculation. We find that the calculated nonlinear susceptibility, χ<sup>(2)</sup>, in AA stacking (550 pm/V) becomes three times as large as AB stacking (170 pm/V) due to the broken inversion symmetry in the AA stacking. The present theoretical prediction is compared with the observed SHG spectra of Janus MoSSe/MoS<sub>2</sub> heterobilayers, in which the peak SHG intensity of AA stacking becomes four times as large as AB stacking. Furthermore, a relatively large, two-dimensional strain (4%) that breaks the <i>C</i><sub>3<i>v</i></sub> point group symmetry of the MoSSe/MoS<sub>2</sub>, enhances calculated χ<sup>(2)</sup> values for both AA (900 pm/V) and AB (300 pm/V) stackings 1.6 times as large as that without strain.