Surface structure of the organic conductor β-(BEDT-TTF)2I3observed by scanning tunneling microscopy [where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene]

Superstructure was observed on the surface of the organic conductor β-(BEDT-TTF${)}_2$ ${\mathrm{I}}_3$ [where BEDT-TTF is bis(ethylene- dithio)tetrathiafulvalene by scanning tunneling microscopy; this shows that surface reconstruction for organic materials can occur. The column structure of BEDT-TTF molecules along the [011] direction was stable and the reconstruction was completed as a result of the change in the relative arrangement of these columns. Many defects consisting of the voids of the BEDT-TTF molecules were also observed. These imperfections of the crystal surface are considered to be due to the instability of the anion structure.