Active transformations of topological structures in light-driven nematic disclination networks

Abstract

SignificanceTopological defects are marvels of nature. Understanding their structures is important for their applications in, for example, directed self-assembly, sensing, and photonic devices. There is recent interest in active motion and transformation of topological defects in active nematics. In these nonequilibrium systems, however, the motion and transformation of disclinations are difficult to control, thereby hindering their applications. Here, we propose a surface-patterned system engendering periodic three-dimensional disclinations, which can be excited by light irradiation and undergo a programmable transformation between different topological states. Continuum simulations recapitulating these topological structures characterize the bending, breaking, and relinking events of the disclinations during the nonequilibrium process. Our work provides an alternative dynamic system in which active transformation of topological defects can be engineered.

Frank-Read Mechanism in Nematic Liquid Crystals

“…In closely related experimental and theoretical work, Jiang et al [37] studied a lattice of surface-pinned disclination segments in a nematic cell. Under director twist imposed by optically rewriting surface anchoring orientation on the opposite substrate, the defects underwent programmable transformations via expansion, merging, and reconfiguration.…”

Geometric theory of topological defects: methodological developments and new trends

“…Geometry of disclinations networks has been theoretically investigated in the literature, sometimes allowing for analytical expressions for the metric tensor [150][151][152]. Several authors have shown the possibility to design arrays of topological linear defects from photopatterning techniques [153][154][155][156][157] and even to manipulate them [158,159]. If this last point opens the possibility to emulate collisions between particles in the 2+1 model, it is even more interesting for the extension of the Deser, Jackiw and 't Hooft model to 3+1 dimensions [70]: matter particles are represented by a gas of piecewise straight string segments that are likely to collide with a higher frequency.…”

Approximate Analytical Solutions of the Schrödinger Equation with Hulthén Potential in the Global Monopole Spacetime

“…The spacetime of cosmic string exerts an impressive influence on the behavior of a physical system, in which effects such as gravitational leasing, self-force, and the gravitational Aharonov-Bohm effect take place. In the literature, different models have been solved in the cosmic string spacetime [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] and disclinations [34][35][36][37][38][39][40][41], which demonstrates the wide range of possibilities of investigation involving these issues.…”