Giant electric field-induced second harmonic generation in polar skyrmions

Sixu Wang; Wei Li; Chenguang Deng; Zijian Hong; Han-Bin Gao; Xiaolong Li; Yueliang Gu; Qiang Zheng; Yongjun Wu; Paul G Evans; Jing-Feng Li; Ce-Wen Nan; Qian Li

doi:10.1038/s41467-024-45755-5

Giant electric field-induced second harmonic generation in polar skyrmions

Nat Commun. 2024 Feb 14;15(1):1374. doi: 10.1038/s41467-024-45755-5.

Authors

Sixu Wang^#¹, Wei Li^#¹, Chenguang Deng¹, Zijian Hong^{2

3}, Han-Bin Gao⁴, Xiaolong Li⁵, Yueliang Gu⁵, Qiang Zheng⁶, Yongjun Wu⁷, Paul G Evans⁸, Jing-Feng Li¹, Ce-Wen Nan¹, Qian Li⁹

Affiliations

¹ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
² School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China. hongzijian100@zju.edu.cn.
³ Research Institute of Zhejiang University-Taizhou, 318000, Taizhou, Zhejiang, China. hongzijian100@zju.edu.cn.
⁴ CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, 100190, Beijing, China.
⁵ Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201204, Shanghai, China.
⁶ CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, 100190, Beijing, China. zhengq@nanoctr.cn.
⁷ School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
⁸ Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
⁹ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China. qianli_mse@tsinghua.edu.cn.

^# Contributed equally.

Abstract

Electric field-induced second harmonic generation allows electrically controlling nonlinear light-matter interactions crucial for emerging integrated photonics applications. Despite its wide presence in materials, the figures-of-merit of electric field-induced second harmonic generation are yet to be elevated to enable novel device functionalities. Here, we show that the polar skyrmions, a topological phase spontaneously formed in PbTiO₃/SrTiO₃ ferroelectric superlattices, exhibit a high comprehensive electric field-induced second harmonic generation performance. The second-order nonlinear susceptibility and modulation depth, measured under non-resonant 800 nm excitation, reach ~54.2 pm V^-1 and ~664% V^-1, respectively, and high response bandwidth (higher than 10 MHz), wide operating temperature range (up to ~400 K) and good fatigue resistance (>10¹⁰ cycles) are also demonstrated. Through combined in-situ experiments and phase-field simulations, we establish the microscopic links between the exotic polarization configuration and field-induced transition paths of the skyrmions and their electric field-induced second harmonic generation response. Our study not only presents a highly competitive thin-film material ready for constructing on-chip devices, but opens up new avenues of utilizing topological polar structures in the fields of photonics and optoelectronics.