Mixing-induced phase stabilization and low-temperature-shifting of ferroelectric nematics

Abstract

Ferroelectric nematic phase is a novel state of matter, i.e. the sixth nematic liquid crystalline state, that represents high degrees of fluidity and polarity simultaneously. Thanks to the unique dielectric response and strong optical nonlinearity originated from the spontaneous polarisation, this new category of materials has begun to receive tremendous interests for developing liquid-based electrooptical applications such as capacitor and memory devices. Recently, based on a massive synthesis, we found the material state can appear in a wide range of molecular modifications under a necessary condition that the molecular dipole is strong enough. However, most of the reported materials exhibit the ferroelectric nematic state at high temperatures and are barely stabilized at room temperature. Here we demonstrate that a proper mixing of ferroelectric nematic materials can expand the temperature range of ferroelectric nematic phase from high temperature about 120ºC down to room temperature about 25ºC. Interestingly, we also show proper mixtures exhibit higher apparent dielectric permittivity and nonlinear optical response than the genuine material.