Topological transition to a vortices lattice in a nematic liquid crystal cell

Abstract

By the application of electromagnetic fields onto an homeotropic nematic liquid crystal cell it is possible to induce vortices, which are particle-type defects with topological charge. The dynamics of the vortices is such that topological charge of the system is conserved, so these defects are always induced in pairs that annihilate after a short amount of time. Using a magnetic ring it is possible to induce a stable vortex triplet that allows the study of its dynamics, which is of an oscillatory kind when a low-frequency voltage is applied. Experimentally, we determine the region of parameters where the vortex triplet is stable, unstable, or becomes a lattice of vortices. We propose an amplitude equation which allow us to describe the vortex dynamics, and numerical simulations show agreement with experimental observations.