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Electric field induced order reconstruction in a nematic cell
R Barberi1, F Ciuchi, G E Durand
1Dipartimento di Fisica, Istituto Nazionale di Fisica della Materia, Universitá di Calabria, Rende, 87036, Cosenza, Italy.
The European Physical Journal. E, Soft Matter
|March 17, 2004
Summary
Researchers observed biaxial switching in nematic liquid crystals using electric fields. This switching changes the material
Area of Science:
- Physics of soft matter
- Liquid crystal physics
- Nonlinear optics
Background:
- Nematic liquid crystals exhibit complex behaviors under external fields.
- Understanding texture transitions is crucial for display and photonic applications.
- Biaxiality in liquid crystals is a key factor influencing their optical and electrical properties.
Purpose of the Study:
- To experimentally observe and explain the biaxial switching phenomenon in nematic liquid crystals.
- To investigate the role of electric fields in inducing topological texture changes.
- To analyze the static and dynamic thresholds associated with this switching.
Main Methods:
- Experimental observation using optical and electrical measurements.
- Application of strong static and short electric field pulses.
- Theoretical explanation using the Landau-de Gennes-Khalatnikov model.
Main Results:
- Observed biaxial switching between distinct nematic liquid crystal textures.
- Identified static and dynamic thresholds for the switching effect.
- Demonstrated a bulk order reconstruction with a pi change in orientation.
- Observed a significant decrease in the static threshold in the presence of a splay-bend wall.
Conclusions:
- The study successfully explains the observed biaxial switching using a Landau-de Gennes-Khalatnikov model.
- The threshold is linked to the exchange of nematic order tensor eigenvalues via biaxial states.
- The presence of splay-bend walls notably reduces the switching threshold.
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