Analogy between periodic patterns in thin smectic liquid crystal films and the intermediate state of superconductors
Bruno Zappone, Atilla Eren Mamuk, Iryna Gryn, Valentina Arima, Alessandra Zizzari, Roberto Bartolino, Emmanuelle Lacaze, Rolfe G. Petschek
Abstract
Significance Microscopic patterns of molecular alignment are easily obtained in smectic LCs subject to conflicting alignment conditions and provide a promising route to the rapid bottom-up fabrication of ordered materials, notably for the organization and manipulation of nanoparticles. A convenient but puzzling feature is that the pattern type can be switched between 1d and 2d by varying the film thickness or applying an electric field. We devised a simple experiment to show that 1d patterns are due to frustration of the smectic phase under a strong distortion of the molecular director field, leading to a mixed nematic–smectic phase. Our finding confirms the long-standing prediction of an “intermediate” LC state based on an analogy with superconductors.