Asymmetric counter propagation of domain walls

• Asymmetric counter propagation of domain walls in nematic liquid crystal.
• Experimental characterization of shape and speed of domain walls and kink formation.
• We propose a phenomenological bistable model with a nonlinear drift.
• Analytical derivation of shape and speed of fronts from the model.

Far from equilibrium systems show different states and domain walls between them. These walls, depending on the type of connected equilibria, exhibit a rich spatiotemporal dynamics. Here, we investigate the asymmetrical counter propagation of domain walls in an in-plane-switching cell filled with a nematic liquid crystal. Experimentally, we characterize the shape and speed of the domain walls. Based on the molecular orientation, we infer that the counter propagative walls have different elastic deformations. These deformations are responsible of the asymmetric counter propagating fronts. Theoretically, based on symmetry arguments, we propose a simple bistable model under the influence of a nonlinear gradient, which qualitatively describes the observed dynamics.