PAIRS OF SI ATOMIC LINES SELF-ASSEMBLING ON THE BETA-SIC(100) SURFACE- AN 8X2-RECONSTRUCTION

We investigate the transition between beta-SiC(100) surface reconstruc tions using scanning tunneling microscopy (filled and empty electronic states). We find the unexpected formation of Si-dimer lines that are self-assembled by pairs with a long-range order resulting in an even 8 x 2 surface reconstruction. This very uncommon surface ordering resul ts in the combination of alternating periodic 3 x 2 and 5 x 2 unit cel ls. In contrast to the beta-SiC(100)3 x 2 surface reconstruction, the Si-dimers are symmetric. Such atomic line pairs provide a novel type o f one dimensional sub-nanostructure potentially having interesting cha racteristics. (C) 1998 Elsevier Science B.V. All rights reserved.