Electrically driven formation and dynamics of swallow-tail solitons in smectic A liquid crystals

Abstract

Electric field driven instabilities of liquid crystals, such as electro-convections, spatiotemporal chaos, backflows, and solitons are of great importance for both fundamental science and practical applications. Here we demonstrate that particle-like multidimensional solitons representing self-localized molecular director deformations can be produced in a smectic A liquid crystal by applying electric fields. These solitons are transformed from focal conic domains with a static structure topologically analogous to parabolic focal conic domains. They lack fore-aft symmetry and move perpendicular to the smectic layers and to the applied electric field direction. During motion, the solitons collide with each other and with colloidal particles and restore their speed and shape after collisions. The rich dynamic behavior and easy control of the solitons make them extremely promising for a broad range of future studies.