Electric-Field-Induced Room-Temperature Antiferroelectric–Ferroelectric Phase Transition in van der Waals Layered GeSe
Zhao Guan, Yi‐Feng Zhao, Xiaoting Wang, Ni Zhong, Xing Deng, Yunzhe Zheng, Jinjin Wang, Dongdong Xu, Ruru Ma, Fangyu Yue, Yan Cheng, Rong Huang, Ping‐Hua Xiang, Zhongming Wei, Junhao Chu, Chun‐Gang Duan
Abstract
Searching van der Waals ferroic materials that can work under ambient conditions is of critical importance for developing ferroic devices at the two-dimensional limit. Here we report the experimental discovery of electric-field-induced reversible antiferroelectric (AFE) to ferroelectric (FE) transition at room temperature in van der Waals layered α-GeSe, employing Raman spectroscopy, transmission electron microscopy, second-harmonic generation, and piezoelectric force microscopy consolidated by first-principles calculations. An orientation-dependent AFE-FE transition provides strong evidence that the in-plane (IP) polarization vector aligns along the armchair rather than zigzag direction in α-GeSe. In addition, temperature-dependent Raman spectra showed that the IP polarization could sustain up to higher than 700 K. Our findings suggest that α-GeSe, which is also a potential ferrovalley material, could be a robust building block for creating artificial 2D multiferroics at room temperature.