Critical fluctuations near the smectic-hexatic phase transition with anticlinic structure

Area of Science:

• Condensed matter physics
• Materials science
• Liquid crystal physics

Background:

• Smectic and hexatic liquid crystal phases exhibit unique structural orders.
• Phase transitions between these phases are crucial for understanding material properties.
• The influence of molecular ordering (synclinic vs. anticlinic) on phase transition dynamics is not fully understood.

Purpose of the Study:

• To investigate the layer compression modulus (B) near smectic-hexatic phase transitions.
• To compare the pretransitional behavior of modulus B in synclinic and anticlinic structures.
• To elucidate the role of in-plane hexatic order in different structural configurations.

Main Methods:

• Experimental measurement of layer compression modulus B.
• Analysis of phase transitions in liquid crystal systems.
• Comparative study of synclinic and anticlinic molecular arrangements.

Main Results:

• In synclinic structures, modulus B exhibited no pretransitional softening near the smectic-hexatic transition.
• In anticlinic structures, significant critical softening of modulus B was observed approaching the smectic-hexatic transition.
• The observed softening in anticlinic structures suggests a distinct mechanism compared to typical smectic-hexatic transitions.

Conclusions:

• The introduction of in-plane hexatic order in anticlinic structures significantly alters the phase transition dynamics.
• Anticlinic ordering leads to critical softening of the layer compression modulus, differing from synclinic behavior.
• These findings highlight the importance of molecular tilt direction in governing liquid crystal phase transition properties.