Biaxial coherence length in a nematic π-cell.

Area of Science:

• Soft Matter Physics
• Liquid Crystal Science
• Materials Science

Background:

• Highly frustrated calamitic nematic phases exhibit strain that can be relaxed by reducing nematic order.
• This relaxation can lead to the local breaking of uniaxial symmetry and the emergence of transient biaxial domains.

Purpose of the Study:

• To estimate the spatial decay length of biaxial disturbances in a π-cell under a weak electric field.
• To characterize the transition from uniaxial splay to bend textures via defect motion.

Main Methods:

• Utilized simple optical retardation measurements to probe the liquid crystal phase.
• Applied a weak electric field to a π-cell containing the nematic liquid crystal.
• Observed and analyzed defect motion during texture transitions.

Main Results:

• Estimated the length scale over which biaxial disturbance decays spatially within the π-cell.
• Characterized the cascade of transitions from uniaxial splay to bend textures.
• Observed slow defect motion accompanying these texture changes.

Conclusions:

• Demonstrated a method to quantify biaxial domain behavior in frustrated nematics.
• Provided insights into the dynamics of texture transitions driven by electric fields.
• Linked strain relaxation mechanisms to observable changes in liquid crystal symmetry and texture.