Observation of Two-Dimensional Hexatic Behavior in Free-Standing Liquid-Crystal Thin Films

Abstract
Bond-orientational ordering in the hexatic-B phase of free-standing liquid-crystal films of two to six molecular layers has been studied quantitatively with electron diffraction. By examination of the scaling relation among the 6n-fold bond-orientational order parameters, it is demonstrated that the two-layer film exhibits truly two-dimensional hexatic behavior. A departure from two-dimensional behavior is observed in the thicker films.