Berry curvature dipole induced giant mid-infrared second-harmonic generation in 2D Weyl semiconductor

• Main Authors: Fu, Qundong, Cong, Xin, Xu, Xiaodong, Zhu, Song, Zhao, Xiaoxu, Liu, Sheng, Yao, Bingqing, Xu, Manzhang, Deng, Ya, Zhu, Chao, Wang, Xiaowei, Kang, Lixing, Zeng, Qingsheng, Lin, Miao-Ling, Wang, Xingli, Tang, Bijun, Yang, Jianqun, Dong, Zhili, Liu, Fucai, Xiong, Qihua, Zhou, Jiadong, Wang, Qijie, Li, Xingji, Tan, Ping-Heng, Tay, Beng Kang, Liu, Zheng
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2024
• Subjects: Engineering::Materials; Berry Curvature Dipoles; Second-Harmonic Generation
• Online Access: https://hdl.handle.net/10356/173283
• Institution: Nanyang Technological University

Due to its inversion-broken triple helix structure and the nature of Weyl semiconductor, 2D Tellurene (2D Te) is promising to possess a strong nonlinear optical response in the infrared region, which is rarely reported in 2D materials. Here, a giant nonlinear infrared response induced by large Berry curvature dipole (BCD) is demonstrated in the Weyl semiconductor 2D Te. Ultrahigh second-harmonic generation response is acquired from 2D Te with a large second-order nonlinear optical susceptibility (χ(2) ), which is up to 23.3 times higher than that of monolayer MoS2 in the range of 700-1500 nm. Notably, distinct from other 2D nonlinear semiconductors, χ(2) of 2D Te increases extraordinarily with increasing wavelength and reaches up to 5.58 nm V-1 at ≈2300 nm, which is the best infrared performance among the reported 2D nonlinear materials. Large χ(2) of 2D Te also enables the high-intensity sum-frequency generation with an ultralow continuous-wave (CW) pump power. Theoretical calculations reveal that the exceptional performance is attributed to the presence of large BCD located at the Weyl points of 2D Te. These results unravel a new linkage between Weyl semiconductor and strong optical nonlinear responses, rendering 2D Te a competitive candidate for highly efficient nonlinear 2D semiconductors in the infrared region.