SURFACE-ANALYSIS OF ORGANIC SUPERCONDUCTORS BY SCANNING PROBE TECHNIQUES - STM AND AFM

Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) have been used for surface characterization of organic superconductors - bis(ethylenedithio)tetrathiafulvalene (ET) salts with linear anions I3-, IBr2-, AuI2- and Cu(NCS)2-. The atomic-scale STM and AFM images correlate well with the surface molecular arrangement, simulated from the X-ray diffraction bulk data: two-dimensional image parameters are close to the crystallographic ones. However, several peculiarities of surface electronic and atomic structure have been revealed. For this purpose the comparison of STM and AFM images of the same surfaces was useful. The variations of atomic scale details in STM images, recorded at different tunneling conditions, are discussed.