DYNAMICS OF VACANCY DEFECTS IN 2-D CRYSTALLINE MONOLAYERS UNDER CHIRAL SMECTIC THIN-FILMS STUDIED BY SCANNING-TUNNELING-MICROSCOPY

Scanning tunnelling microscopy (STM) can be used to image adsorbed org anic molecules in real space and real time. The technique seems especi ally well suited for imaging 2-D crystalline monolayers formed under l iquid crystal films. In addition to observing perfect 2-D crystals, ST M provides the ability to observe crystal defects, and to observe how these defects evolve over time. In this study two different vacancy de fects in 2-D lamellar monolayers of chiral liquid crystal molecules un der bulk smectic films were observed in situ. Both vacancies showed dy namic behaviour and an unexpected transport anisotropy.