范德华铁性材料对于实现下一代功能器件具有丰富的潜力。其中,层状β\'-In2Se3以其复杂的超晶格和畴结构吸引了研究人员。与铁电α-In2Se3相反,对β\'-In2Se3铁性的理解仍不清楚,因为铁电,反铁电,和铁弹性特性已经在这种材料中单独报道。为了开发有用的应用程序,有必要了解微观结构特性及其与宏观器件特性的相关性。在这里,使用扫描透射电子显微镜(STEM),我们观察到,由于反铁电和铁电结构有序之间的竞争,偶极子的排列偏离了理想的双反平行反铁电特性。由于二次谐波的产生,四维STEM,和平面内压电响应力显微镜,远程反演破除对称性,未补偿的局部偏振,净极化域得到了明确的验证,揭示β'-In2Se3为平面内亚铁电层状材料。此外,我们的器件研究揭示了由于极化切换而导致的不同类型的类似电阻切换行为,缺陷迁移,和缺陷诱导的电荷捕获/去捕获过程。
van der Waals ferroic materials exhibit rich potential for implementing future generation functional devices. Among these, layered β\'-In2Se3 has fascinated researchers with its complex superlattice and domain structures. As opposed to ferroelectric α-In2Se3, the understanding of β\'-In2Se3 ferroic properties remains unclear because ferroelectric, antiferroelectric, and ferroelastic characteristics have been separately reported in this material. To develop useful applications, it is necessary to understand the microscopic structural properties and their correlation with macroscopic device characteristics. Herein, using scanning transmission electron microscopy (STEM), we observed that the arrangement of dipoles deviates from the ideal double antiparallel antiferroelectric character due to competition between antiferroelectric and ferroelectric structural ordering. By virtue of second-harmonic generation, four-dimensional STEM, and in-plane piezoresponse force microscopy, the long-range inversion-breaking symmetry, uncompensated local polarization, and net polarization domains are unambiguously verified, revealing β\'-In2Se3 as an in-plane ferrielectric layered material. Additionally, our device study reveals analogous resistive switching behaviors of different types owing to polarization switching, defect migration, and defect-induced charge trapping/detrapping processes.