Sui Fengrui, Yu Yilun, Chen Ju, Qi Ruijuan, Ge Rui, Zheng Yufan, Liu Beituo, Jin Rong, Gong Shijing, Yue Fangyu, Chu Junhao
Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, China.
Engineering Research Center of Nanophotonics & Advanced Instrument (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, China.
Nat Commun. 2025 Feb 20;16(1):1810. doi: 10.1038/s41467-025-57138-5.
Fundamentally, ferroelectrics must belong to a noncentrosymmetric space group, limiting the exploration of more new ferroelectric materials. We circumvent this limitation by triggering structure distortion and inducing ferroelectricity in centrosymmetric van der Waals group-IV monochalcogenide GeSe semiconductor that features unexpected intrinsic out-of-plane antiferroelectricity. Double-type and single-type hysteresis loops from electric measurements, bonding distortion observed in in-situ atomic imaging, and perpendicular polarization uncovered by first-principles calculations, confirm the intrinsic out-of-plane antiferroelectricity and the antiferroelectric-ferroelectric transition induced by the vertical external electric-field. The hidden out-of-plane antiferroelectricity and field induced ferroelectric polarization in spatial-inversion symmetric GeSe makes it a new member of van der Waals layered semiconductors with both in-plane and out-of-plane ferroelectricity, and possibly, can be extended to all group-IV monochalcogenides and other centrosymmetric van der Waals layered materials.
从根本上说，铁电体必须属于非中心对称空间群，这限制了对更多新型铁电材料的探索。我们通过触发结构畸变并在具有意外本征面外反铁电性的中心对称范德华IV族单硫属化物GeSe半导体中诱导铁电性，规避了这一限制。电学测量中的双型和单型滞后回线、原位原子成像中观察到的键合畸变以及第一性原理计算揭示的垂直极化，证实了本征面外反铁电性以及垂直外部电场诱导的反铁电-铁电转变。空间反演对称的GeSe中隐藏的面外反铁电性和场致铁电极化使其成为具有面内和面外铁电性的范德华层状半导体的新成员，并且可能扩展到所有IV族单硫属化物和其他中心对称的范德华层状材料。
