Electric field-driven reconfigurable multistable topological defect patterns

Area of Science:

• Soft Matter Physics
• Materials Science
• Nonlinear Dynamics

Background:

• Topological defects are fundamental to symmetry breaking and phase transitions.
• Nematic liquid crystals (NLCs) offer a versatile platform for studying and applying topological defects.
• Controlling defect configurations is key to unlocking technological applications.

Purpose of the Study:

• To investigate the switching of stable, chargeless disclination patterns in NLCs using external electric fields.
• To demonstrate multistable control over defect configurations in a 4x4 lattice.
• To explore the fundamental properties of chargeless line defects and their interactions.

Main Methods:

• Theoretical modeling using the Landau-de Gennes phenomenological approach.
• Experimental manipulation via an Atomic Force Measurement scribing method for substrate defect patterning.
• Observation and analysis using polarized optical microscopy.
• Numerical simulations to predict and validate defect behavior.

Main Results:

• Stabilization of an "alphabet" of up to 18 unique line defect configurations in a 4x4 lattice of alternating s=±1 surface defects.
• Demonstration of multistable rewiring of these defect patterns using electric field manipulation.
• Experimental and numerical evidence of chargeless line defects exhibiting defect-antidefect properties.
• Observation of attractive interactions between antiparallel disclinations, leading to rewiring or annihilation.

Conclusions:

• A robust method for controlling topological defect configurations in NLCs via electric fields has been established.
• The findings present a proof-of-concept for applications in multistable optical displays and rewirable nanowires.
• The study provides fundamental insights into the behavior and interactions of chargeless line defects in liquid crystals.