Layer Dependent Ferroelectricity and Electromechanically Coupled Polarization in Two-Dimensional 1T′-ReS2
Zhengyue Li, Jinfeng Yang, Yinfei Xie, Yang He, Xiaonan Wang, Bo Zou, Bingxuan Zhu, Zhongqi Ren, Chu Xiao, Yangyang Si, Yuxuan Yang, Kangjin Zhou, Jingkai Qin, Chengyan Xu, Hao Tian, Haijun Wu, Huarui SunAbstract
Two-dimensional (2D) van der Waals (vdW) materials with sliding ferroelectricity exhibit an enormous potential for next-generation nanodevices. Among these, 1T′-ReS2 with an ultralow symmetry stands out as a pivotal candidate. However, the fundamental scientific mechanism underlying sliding ferroelectricity in 1T′-ReS2 remains poorly understood due to the complexity of its crystal structure. By integrating STEM, DFT calculations, and KPFM, this work resolves the correlation between AA/AB stacking and polarization in 1T′-ReS2. PFM and STEM characterizations further reveal that the observed ferroelectric-like PFM signals originate from flexoelectric-like wrinkles rather than from intrinsic ferroelectric switching. Finally, device measurements provide evidence of sliding ferroelectricity in even-layer AB-stacked ReS2 and demonstrate its application potential.