Particle-based model of liquid crystal skyrmion dynamics.

Area of Science:

• Soft Matter Physics
• Liquid Crystals
• Nonlinear Dynamics

Background:

• Recent experiments show complex collective dynamics in active liquid crystal skyrmions.
• Understanding the fundamental mechanisms driving skyrmion motion is crucial for controlling these systems.

Purpose of the Study:

• To develop a coarse-grained particle-based model for active liquid crystal skyrmion dynamics.
• To elucidate the physical mechanism behind skyrmion motion, specifically the role of director field reorientation.

Main Methods:

• Developed a particle-based model based on squirming undulations of director twist in skyrmion cores.
• Mapped director distortions from a fine-grained Frank-Oseen continuum model to an effective asymmetric force.
• Validated the model by reproducing skyrmion dynamics, including velocity reversal with modulated electric fields.

Main Results:

• The model accurately reproduces skyrmion dynamics, including velocity reversal dependent on driving voltage frequency.
• Derived approximate analytical expressions for model parameters, linking them to cholesteric pitch and electric field strength.
• Demonstrated that skyrmion motion arises from director field reorientation, not mass flow.

Conclusions:

• The developed coarse-grained model effectively captures the essential physics of active liquid crystal skyrmion motion.
• The findings provide a simplified yet accurate framework for studying and predicting skyrmion behavior in response to electric fields.