Remarkably enhanced second harmonic generation in Janus HfXY (X, Y = O, S, Se, Te; X ≠ Y) monolayers
4 affiliations
- 1School of Physics and Electronic Engineering, Jiangsu University, Zhenjiang, Jiangsu, China
- 2Quantum Sensing and Agricultural Intelligence Detection Engineering Center of Jiangsu Province, Zhenjiang, China
- 3School of Physics and Electronic Information Engineering, Ningxia Normal University, Guyuan, Ningxia, China
- 4Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, School of Physics, Dalian, China
Abstract
Designing new two-dimensional (2D) materials with enhanced second harmonic generation (SHG) and uncovering the underlying mechanisms is crucial for enabling high-performance nonlinear photonics. In this work, we design a new Janus structure HfXY (X, Y = O, S, Se, Te) with tetrahedral phase and investigate its structural stability, electronic properties, and SHG responses using first-principles calculations. Phonon spectrum analysis confirms that three of these monolayers, HfOSe, HfOTe, and HfSTe, are dynamically stable semiconductors. All three dynamically stable Janus monolayers are indirect semiconductors with valence band maxima located at the Γ point and conduction band minima at the S point. HfOSe and HfSTe monolayers exhibit pronounced out-of-plane SHG with nonlinear susceptibility components reaching the order of 102 pm/V, 1–2 orders of magnitude higher than in conventional bulk nonlinear optical crystals, and the charge asymmetry also enhances the SHG response of HfOSe and HfSTe beyond that of their pristine counterparts. By uncovering the intrinsic origins of their outstanding SHG activity, our findings position tetragonal Janus monolayers as a promising materials platform, stimulating the exploration of multiphase Janus systems and their implementation in cutting-edge nonlinear photonic devices.
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BibTeX
@article{li2026remarkably,
title = {{Remarkably enhanced second harmonic generation in Janus HfXY (X, Y = O, S, Se, Te; X ≠ Y) monolayers}},
author = {Shi-Qi Li and Shi-Qi Li and Zhijie Lei and Zhijie Lei and Ruizhao LI and Yunxiao Ban and Yunxiao Ban and Xiaozhendong Bao and Jinghong Ding and Jinghong Ding and Hanlin Su and Hanlin Su and Anbing Zhang and Hongfei Yin and Hongfei Yin},
journal = {Frontiers in Chemistry},
year = {2026},
month = oct,
doi = {10.3389/fchem.2026.1986563},
url = {https://doi.org/10.3389/fchem.2026.1986563},
note = {CC BY},
}
RIS
TY - JOUR
TI - Remarkably enhanced second harmonic generation in Janus HfXY (X, Y = O, S, Se, Te; X ≠ Y) monolayers
AU - Shi-Qi Li
AU - Shi-Qi Li
AU - Zhijie Lei
AU - Zhijie Lei
AU - Ruizhao LI
AU - Yunxiao Ban
AU - Yunxiao Ban
AU - Xiaozhendong Bao
AU - Jinghong Ding
AU - Jinghong Ding
AU - Hanlin Su
AU - Hanlin Su
AU - Anbing Zhang
AU - Hongfei Yin
AU - Hongfei Yin
PY - 2026
DA - 2026/10/26
JO - Frontiers in Chemistry
DO - 10.3389/fchem.2026.1986563
UR - https://doi.org/10.3389/fchem.2026.1986563
AB - Designing new two-dimensional (2D) materials with enhanced second harmonic generation (SHG) and uncovering the underlying mechanisms is crucial for enabling high-performance nonlinear photonics. In this work, we design a new Janus structure HfXY (X, Y = O, S, Se, Te) with tetrahedral phase and investigate its structural stability, electronic properties, and SHG responses using first-principles calculations. Phonon spectrum analysis confirms that three of these monolayers, HfOSe, HfOTe, and HfSTe, are dynamically stable semiconductors. All three dynamically stable Janus monolayers are indirect semiconductors with valence band maxima located at the Γ point and conduction band minima at the S point. HfOSe and HfSTe monolayers exhibit pronounced out-of-plane SHG with nonlinear susceptibility components reaching the order of 102 pm/V, 1–2 orders of magnitude higher than in conventional bulk nonlinear optical crystals, and the charge asymmetry also enhances the SHG response of HfOSe and HfSTe beyond that of their pristine counterparts. By uncovering the intrinsic origins of their outstanding SHG activity, our findings position tetragonal Janus monolayers as a promising materials platform, stimulating the exploration of multiphase Janus systems and their implementation in cutting-edge nonlinear photonic devices.
SN - 2296-2646
ER -