Nonlinear Optical Responses of Janus MoSSe/MoS2 Heterobilayers Optimized by Stacking Order and Strain

Nguyen Tuan Hung; Kunyan Zhang; Vuong Van Thanh; Yunfan Guo; Alexander A Puretzky; David B Geohegan; Jing Kong; Shengxi Huang; Riichiro Saito

doi:10.1021/acsnano.3c04436

Nonlinear Optical Responses of Janus MoSSe/MoS₂ Heterobilayers Optimized by Stacking Order and Strain

ACS Nano. 2023 Oct 24;17(20):19877-19886. doi: 10.1021/acsnano.3c04436. Epub 2023 Aug 29.

Authors

Nguyen Tuan Hung^{1

2}, Kunyan Zhang³, Vuong Van Thanh⁴, Yunfan Guo⁵, Alexander A Puretzky⁶, David B Geohegan⁶, Jing Kong⁷, Shengxi Huang³, Riichiro Saito²

Affiliations

¹ Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan.
² Department of Physics, Tohoku University, Sendai 980-8578, Japan.
³ Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States.
⁴ School of Mechanical Engineering, Hanoi University of Science and Technology, Hanoi 100000, Viet Nam.
⁵ Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310058, China.
⁶ Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
⁷ Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.

PMID: 37643404
DOI: 10.1021/acsnano.3c04436

Abstract

Nonlinear optical responses in second harmonic generation (SHG) of van der Waals heterobilayers, Janus MoSSe/MoS₂, 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⁽²⁾, 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/MoS₂ 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 C_3v point group symmetry of the MoSSe/MoS₂, enhances calculated χ⁽²⁾ values for both AA (900 pm/V) and AB (300 pm/V) stackings 1.6 times as large as that without strain.

Keywords: 2D Janus heterobilayers; first-principles calculations; second-harmonic generation; stacking effect; strain engineering; time-dependent density-functional theory.