STM OBSERVATION OF THE ATOMIC-HYDROGEN ADSORPTION ON THE SI(111)4X1-IN SURFACE

We have used scanning tunneling microscopy and low-energy electron dif fraction to study early stages of atomic hydrogen interaction with Si( 111)4 X 1-In surface at temperature 300 degrees C. Indium rows of the 4 X 1-In structure were removed during interaction with atomic hydroge n and Si(111)4 X 1-H and Si(111)1 X 1-H coexisting regions were observ ed. This 4 X 1-H region was ascribed to the substrate reconstruction i n accordance with the previous observations. Thus the substrate recons truction for the Si(111)4 X 1-In was directly observed and evidenced, These results are interpreted on the basis of the recently proposed di merized chain models for the Si(111)3 X 1 Ag and alkali metals reconst ruction.