A Helical Layered Liquid Crystal Phase

A novel liquid crystal phase was discovered which exhibits two seemingly incongruous characteristic features; namely, a smectic-A like layered structure along with a macroscopic (1micron) helical structure with the helical axis parallel to the layer planes. Th layered structure results in resolution-limited x-ray diffraction peaks while the helix makes the phase optically iridescent. Such a twist distortion penetrating a layered structure was shown by deGennes to be analogous to a magnetic field penetrating a superconductor and necessitates the existence of a regular array of screw dislocations. If the array of screw dislocations is ordered than the new phase would be a liquid crystal analog of the Abrikosov flux lattice phase observed in type II superconductors.