SI(111)-5X1-AU RECONSTRUCTION AS STUDIED BY SCANNING TUNNELING MICROSCOPY

Scanning tunneling microscopy (STM) is used to characterize the Si(111)-5×1-Au surface reconstruction that occurs at 0.4 monolayers Au. We observe three equivalent domains of the 5×1 structure, which appear as rows oriented along 1»10 directions with a five-unit-cell separation. STM images reveal an asymmetric structure with a two-unit-cell periodicity along any given row. The phase of this two-unit-cell periodicity is not correlated between rows, however, preventing any long-range 5×2 order. In addition, bright features are commonly seen along the 5×1 rows, always located at multiples of the two-unit-cell spacing. © 1990 The American Physical Society.