FORMATION OF 2-DIMENSIONAL MIXED-CRYSTALS ON GRAPHITE OBSERVED BY SCANNING-TUNNELING-MICROSCOPY

Scanning tunneling microscopy (STM) is a powerful tool for observing o rganic molecules in real space. In this study, five similar ferroelect ric liquid crystal (FLC) materials (four unsaturated isomers and the s aturated parent) adsorbed on graphite were examined by scanning tunnel ing microscopy as neat compounds and as mixtures. The unit cells of ad sorbed monolayers formed by the mixtures showed distinct differences f rom the unit cells of the pure compounds, suggesting that mixed monola yers were formed. The saturated compound formed two structures having different unit cells, and it appeared that the difference in energies was very small. Changing the location of the double bond had no observ able effect on the adsorbed monolayers, and the isolated double bonds were not observed.