Studies of surface-induced layer-by-layer two-stage phase transformations

Utilizing our high-resolution ac calorimeter, optical reflectivity, and electron diffraction, we have found a few very interesting phenomena associated with the free-standing films of the N-(4-n-butyloxybenzylidene)-4-n-octylaniline (4O.8) compound. Upon cooling from the smectic-A phase, the outer surface layers display a distinct hexatic-B order and subsequently transforms into crystal-B phase through a two-stage transformation. Each stage is found to be first order. The film exhibits a layer-by-layer ordering transitions developed from the film/vapor interface inwardly.