Switchable hidden spin polarization and negative Poisson's ratio in two-dimensional antiferroelectric wurtzite crystals

• Published in: Journal of semiconductors 2023-12, Vol.44 (12), p.122101-87
• Main Authors: Ma, Zhuang, Jiang, Jingwen, Wang, Gui, Zhang, Peng, Sun, Yiling, Qian, Zhengfang, Zheng, Jiaxin, Xiong, Wen, Wang, Fei, Zhang, Xiuwen, Huang, Pu
• Format: Article
• Language: English
• Subjects: hidden spin polarization; multiferroics; negative Poisson's ratio; wurtzite crystal
• ISSN: 1674-4926; 2058-6140
• DOI: 10.1088/1674-4926/44/12/122101

Two-dimensional (2D) antiferroelectric materials have raised great research interest over the last decade. Here, we reveal a type of 2D antiferroelectric (AFE) crystal where the AFE polarization direction can be switched by a certain degree in the 2D plane. Such 2D functional materials are realized by stacking the exfoliated wurtzite ( wz ) monolayers with “self-healable” nature, which host strongly coupled ferroelasticity/antiferroelectricity and benign stability. The AFE candidates, i.e., ZnX and CdX (X = S, Se, Te), are all semiconductors with direct bandgap at Γ point, which harbors switchable antiferroelectricity and ferroelasticity with low transition barriers, hidden spin polarization, as well as giant in-plane negative Poisson's ratio (NPR), enabling the co-tunability of hidden spin characteristics and auxetic magnitudes via AFE switching. The 2D AFE wz crystals provide a platform to probe the interplay of 2D antiferroelectricity, ferroelasticity, NPR, and spin effects, shedding new light on the rich physics and device design in wz semiconductors.