Vats Aditya, Puri Sanjay, Banerjee Varsha
Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India.
School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Phys Rev E. 2022 Oct;106(4-1):044701. doi: 10.1103/PhysRevE.106.044701.
The biaxial phase in nematic liquid crystals has been elusive for several decades after its prediction in the 1970s. A recent experimental breakthrough was achieved by Liu et al. [Proc. Natl. Acad. Sci. USA 113, 10479 (2016)0027-842410.1073/pnas.1601235113] in a liquid-crystalline medium with magnetic nanoparticles. They exploited the different length scales of dipolar and magnetonematic interactions to obtain an equilibrium state where the magnetic moments are at an angle to the nematic director. This tilt introduces a second distinguished direction for orientational ordering or biaxiality in the two-component system. Using coarse-grained Ginzburg-Landau free-energy models for the nematic and magnetic fields, we provide a theoretical framework which allows for the manipulation of morphologies and quantitative estimates of biaxial order.
向列型液晶中的双轴相自20世纪70年代被预测以来，几十年来一直难以捉摸。最近，刘等人[《美国国家科学院院刊》113, 10479 (2016)0027 - 842410.1073/pnas.1601235113]在含有磁性纳米颗粒的液晶介质中取得了实验突破。他们利用偶极相互作用和磁向列相互作用的不同长度尺度，获得了一种平衡态，其中磁矩与向列指向矢成一定角度。这种倾斜在二元系统中引入了第二个用于取向有序化或双轴性的显著方向。我们使用针对向列场和磁场的粗粒化金兹堡 - 朗道自由能模型，提供了一个理论框架，该框架允许对形态进行操控并对双轴序进行定量估计。
