New quasiperiodic structures in nematic liquid crystals

Area of Science:

• Materials Science
• Condensed Matter Physics

Background:

• Liquid crystals exhibit self-alignment, forming topological defects at domain boundaries.
• These defects reveal information about molecular ordering under competing constraints.

Purpose of the Study:

• To experimentally demonstrate a novel mechanism for generating spatially oscillatory domain walls in nematic liquid crystals.
• To develop a predictive theory for liquid crystal director evolution in response to electric fields.

Main Methods:

• Applying a horizontal electric field to homeotropically aligned nematic liquid crystals.
• Investigating domain wall formation and stability across a range of electric field frequencies.
• Developing a general theory for 3D liquid crystal director evolution in 2D varying fields.

Main Results:

• Spatially oscillatory domain walls were generated at low electric field frequencies.
• These oscillatory domain walls remained stable as frequency increased.
• At higher frequencies (kHz), non-oscillatory domain walls formed.
• The developed theory accurately predicts the time-dependent behavior and stability of both oscillatory and straight domain walls.

Conclusions:

• A new method for creating dynamic topological defects in liquid crystals was established.
• The study confirms the stability of both oscillatory and straight domain walls under specific electric field conditions.
• The theoretical framework provides a valuable tool for understanding liquid crystal behavior in complex fields.