In view of the special importance of the IV(103)-(1 x 1)-III surface struct
ures to the III/IV interfacial systems, in this paper the atomic structure
of the Si(103)-(1 x 1)-In surface is studied by means of scanning tunneling
microscopy. The model that contains an indium and a silicon adatom in a un
it cell, which has passed the test of low energy electron diffraction calcu
lations, is confirmed to be correct. The dangling bond of the silicon adato
m is found to be essentially empty.