Electrically Switchable Multi-Stable Topological States Enabled by Surface-Induced Frustration in Nematic Liquid...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Surface patterning in liquid crystal (LC) cells directs molecular self-assembly.
• Conflicting anchoring patterns can induce surface frustration and defects.
• Elastic deformations can achieve defect-free configurations, but electrical stimuli may introduce disclinations.

Purpose of the Study:

• To investigate the creation and control of multi-stable states in LC cells with crossed anchoring patterns.
• To explore the role of electrical stimuli and geometrical parameters in forming these states.
• To demonstrate the potential for smart window applications with tunable transparency.

Main Methods:

• Utilized dual-frequency liquid crystals with frequency-dependent dielectric properties.
• Applied electric field treatments and varied geometrical parameters.
• Employed Q-tensor simulations for configuration retrieval and optical simulations for validation against microscopy images.

Main Results:

• Achieved defect-free bulk configurations through elastic deformations.
• Demonstrated electrical stimulus-induced disclination lines that persist without voltage.
• Obtained repeatable switching between multi-stable states (with and without disclinations) using frequency-dependent dielectric properties.
• Confirmed topological protection and energy barriers for observed metastability.

Conclusions:

• Multi-stable topological states in LC cells can be precisely controlled by electrical stimuli and geometrical parameters.
• These states exhibit distinct optical properties, enabling switching between transparent and opaque states.
• The findings offer opportunities for developing low-energy smart windows and advanced optical devices.