铁电向列相液晶的剪切模式直接压电响应
Shear-mode Direct Piezoelectric Response of Ferroelectric Nematic Liquid Crystals
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中文总结 AI 辅助
研究铁电向列相液晶的剪切模式直接压电响应，通过对RM734和DIO进行周期性剪切诱导电流和振荡流变学测量，定量确定了剪切模式直接压电耦合常数，并提出铁电极化流动取向导致直接压电响应的物理机制。
中文摘要 AI 辅助
压电性（机械变形与电信号之间的线性耦合）最初仅在固体晶体中被观察到。最近发现液态铁电向列相液晶也具有压电性。然而，到目前为止仅对其逆压电信号（施加电压引起的机械变形）进行了定量测量。在这项工作中，我们对两种典型的铁电向列相化合物RM734和DIO进行了周期性剪切诱导电流和振荡流变学测量。通过基波和二次谐波电流信号的温度、频率和应变相关结果以及振荡流变学结果，我们能够定量确定剪切模式直接压电耦合常数。两种材料的这些值相似，并与先前逆压电测量结果进行了比较。我们提出了一种物理机制，其中铁电极化的流动取向导致直接压电响应。
英文摘要
Piezoelectricity (linear coupling between mechanical deformation and electric signal) was originally observed only in solid crystals. Recently, it was discovered that liquid ferroelectric nematic liquid crystals are also piezoelectric. However, so far only their converse piezoelectric signals (applied voltage-induced mechanical deformation) were measured quantitatively. In this work, we have carried out periodic shear-induced electric current and oscillatory rheology measurements on the two archetypic ferroelectric nematic compounds, RM734 and DIO. From temperature, frequency and strain dependent results of the first and second harmonic current signals together with the results from oscillatory rheometry, we were able to quantitatively determine the shear-mode direct piezoelectric coupling constants. These values are similar for both materials and are compared to results of previous converse piezoelectric measurements. We propose a physical mechanism in which the flow alignment of ferroelectric polarization leads to the direct piezoelectric response.
