近日，西安交通大学S. Shen团队研究了水冰的挠曲电性和表面铁电性。该研究于2025年8月27日发表在《自然—物理学》杂志上。
在环境压力下的冰冻水——普通的冰，也被称为六边形Ih冰——是一种非极性物质，尽管单个水分子是极性的。因此，冰不具有压电性，不能在压力下发电。然而，原则上它可以在弯曲下产生电，因为极化和应变梯度之间的耦合（挠曲电性）总是被对称所允许的。
研究组测量了冰的挠曲电性，发现它与基准电陶瓷如TiO2和SrTiO3相当。此外，柔性电测量对表面边界条件的敏感性揭示了铁电相变在160K被限制在冰盖的近地表区域内。除了在寒冷地区原位制造的低成本传感器的潜在应用之外，这些发现对人们对涉及冰的自然现象的理解产生了深远的影响：对雷暴云中冰-霰碰撞产生的柔性电荷密度的计算与在此类事件中转移的实验电荷进行了有利的比较，这表明挠曲电性可能参与了闪电的产生。
附：英文原文
Title: Flexoelectricity and surface ferroelectricity of water ice
Author: Wen, X., Ma, Q., Mannino, A., Fernandez-Serra, M., Shen, S., Catalan, G.
Issue&Volume: 2025-08-27
Abstract: Frozen water at ambient pressure—common ice, also known as hexagonal Ih ice—is a non-polar material, even though individual water molecules are polar. Consequently, ice is not piezoelectric and cannot generate electricity under pressure. However, it may in principle generate electricity under bending, because the coupling between polarization and strain gradient (flexoelectricity) is always allowed by symmetry. Here we measure the flexoelectricity of ice and find it to be comparable to that of benchmark electroceramics such as TiO2 and SrTiO3. Moreover, the sensitivity of flexoelectric measurements to surface boundary conditions has revealed a ferroelectric phase transition around 160K confined within the near-surface region of the ice slabs. Beyond potential applications in low-cost transducers made in situ in cold locations, these findings have profound consequences for our understanding of natural phenomena involving ice: our calculations of the flexoelectric charge density generated in ice–graupel collisions inside thunderstorm clouds compare favourably to the experimental charge transferred in such events, suggesting a possible participation of ice flexoelectricity in the generation of lightning.
DOI: 10.1038/s41567-025-02995-6
Source: https://www.nature.com/articles/s41567-025-02995-6