Solitons and defects in nematic liquid crystals under a simple shear flow and in a static external magnetic field

作     者：罗开富 蒋秀丽 杨玉良 

作者机构：Department of Macromolecular ScienceKey Laboratory of Molecular Engineering of Polymers of State Ministry EducationFudan University 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2008年第17卷第7期

页      面：2600-2609页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China (Grant No 29874011) State Basic Research Program of China (Grant No 1999064800) 

主　　题：liquid crystals defects solitons 

摘      要：Under a simple shear flow and in a static external magnetic field, the production of defects in the director-aligning regime of nematic liquid crystals has been investigated in terms of the Leslie-Ericksen theory. The equation of motion of the nematic director, which conforms to the driven over-damped sine-Gordon equation, has a soliton solution of the amplitude w. We show that the stationary state with the director uniformly oriented at a Leslie angle is only a metastable state and the potential, which governs the motion of the director, has a nmnber of stable stationary states. For a strong magnetic field, the higher energy barrier between the stable and unstable states leads the director to be locked along the magnetic field direction. However, at the appropriate shear rate and magnetic field the defects, which appear as a stable solitary solution, can be nucleated from a uniformly aligned nematic liquid crystal. We have calculated the stationary travelling velocity of the solitary waves and the distance between a pair of defects.