Electric-Field-Induced Room-Temperature Antiferroelectric-Ferroelectric Phase Transition in van der Waals Layered GeSe

摘要

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 alpha-GeSe, employing Raman spectroscopy, transmission electron microscopy, second-harmonic generation, and piezoelectric force microscopy consolidated by first-principles calculations. An orientationdependent AFE-FE transition provides strong evidence that the in-plane (IP) polarization vector aligns along the armchair rather than zigzag direction in alpha-GeSe. In addition, temperature-dependent Raman spectra showed that the IP polarization could sustain up to higher than 700 K. Our findings suggest that alpha-GeSe, which is also a potential ferrovalley material, could be a robust building block for creating artificial 2D multiferroics at room temperature.

关键词