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arXiv · 2606.21149

Room-Temperature Noncolinear Ferroelectricity in van der Waals WO$_2$Cl$_2$ with a Wide Bandgap

Yu Xing·Ning Ding·Zhipeng Wang·Zhiwen Pan·Lei Guo·Guowei Du·Yangrui Liu·Xiaoxing Cao·Ran Su·Mengting Jiang·Xuezhi Ma·Xiyu Chen·Junchao Zhang·Xinyu Yang·Haoran Ye·Honghong Yao·Rui Feng·Dexiang Chen·Le-Ping Miao·Yumeng You·Zejun Li·Dongsheng Song·Linglong Li·Shuai Dong
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Abstract

Low-dimensional ferroelectrics are attractive for their promising prospects in nanoelectronics. Compared with widely-used ferroelectric perovskites, most low-dimensional ferroelectrics exhibit several inborn weaknesses such as small bandgaps (mostly <2 eV, i.e. semiconductors-like) or faint polarizations (e.g. $<1$ $\mu$C/cm$^2$ for sliding ferroelectrics even if their bandgaps can be large). Here we experimentally demonstrate the room-temperature ferroelectricity of van der Waals WO$_2$Cl$_2$ . The well-tested d0 rule inherited from ferroelectric perovskites leads to a large dipole (~3 e\AA) from the off-center displacement of W$^6+$ ion and a wide bandgap of 2.80 eV. Its ferroelectricity is proved by multiple characterizations including second harmonic generation, piezoresponse force microscopy, and ferroelectric hysteresis loops. More interestingly, the exotic noncollinear dipole order is directly observed at the atomic level by integrated differential phase contrast scanning transmission electron microscopy. Our work paves an alternative route for low-dimensional ferroelectrics to pursue excellent ferroelectric performance and distinct physics of polarity.

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Yu Xing, Ning Ding, Zhipeng Wang, Zhiwen Pan, Lei Guo, Guowei Du, Yangrui Liu, Xiaoxing Cao, Ran Su, Mengting Jiang, Xuezhi Ma, Xiyu Chen, Junchao Zhang, Xinyu Yang, Haoran Ye, Honghong Yao, Rui Feng, Dexiang Chen, Le-Ping Miao, Yumeng You, Zejun Li, Dongsheng Song, Linglong Li, Shuai Dong. 2026-06-19. Room-Temperature Noncolinear Ferroelectricity in van der Waals WO$_2$Cl$_2$ with a Wide Bandgap. https://doi.org/10.1103/zjyw-z6s6

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