de Jeu Wim H, Fera Andrea, Konovalov Oleg, Ostrovskii Boris I
FOM-Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Feb;67(2 Pt 1):020701. doi: 10.1103/PhysRevE.67.020701. Epub 2003 Feb 6.
The crystallization of a single liquid top layer of smectic membranes of the compound 4O.8 has been studied with grazing-incidence x-ray diffraction. As this process takes place in two steps, involving an intermediate hexatic smectic-B layer before the final crystalline-B surface structure is reached, it provides a model for melting in two dimensions. The positional order has been investigated quantitatively by measuring the scattering profiles and the associated correlation lengths. The surface liquid-hexatic phase transition is found to be continuous, while the hexatic-crystal transition is weakly first order with an abrupt change of the in-plane positional correlations. The surface phase transitions do not modify the liquid in-plane structure of the interior layers.
