Ferroelectric ordering in liquids is a fundamental question of physics. Here, we show that ferroelectric ordering of the molecules causes the formation of recently reported splay nematic liquid-crystalline phase. As shown by dielectric spectroscopy, the transition between the uniaxial and the splay nematic phase has the characteristics of a ferroelectric phase transition, which drives an orientational ferroelastic transition via flexoelectric coupling. The polarity of the splay phase was proven by second harmonic generation imaging, which additionally allowed for determination of the splay modulation period to be of the order of 5-10 microns, also confirmed by polarized optical microscopy. The observations can be quantitatively described by a Landau-de Gennes type of macroscopic theory.

中文翻译：

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向列型液晶中的铁电-铁弹性相变。

液体中的铁电有序性是物理学的基本问题。在这里，我们表明分子的铁电有序导致最近报道的八字向列液晶相的形成。如介电谱所示，单轴相和八字向列相之间的跃迁具有铁电相变的特性，该特性通过柔电耦合驱动定向铁磁弹性跃迁。展开相位的极性通过二次谐波生成成像证明，其还允许将展开调制周期确定为5-10微米的量级，这也通过偏振光学显微镜确认。观测值可以用Landau-de Gennes类型的宏观理论定量地描述。