Scanning tunneling microscopy evidence of background contamination-induced 2=1 ordering of the b-SiC 100/ c 4=2/ surface

We use atom-resolved scanning tunneling microscopy STM.to investigate in the real space, the effects of slight contamination on the b-SiC 100.surface structure. We find that a 2=1 surface ordering is induced by background surface contamination of the c 4=2.surface reconstruction. This results from the disruption of the latter having alternately up- and down-dimer AUDD.ordering, with all dimers coming at the same height, leading to adsorbate-induced electronic redistribution. This work, which stresses the very high surface sensitivity of the b-SiC 100.c 4=2.surface reconstruction, is especially relevant in achieving high quality Awell definedB b-SiC 100.surfaces. q2000 Elsevier Science B.V. All rights reserved.