Low-energy electron diffraction study of surfaces of antimony and bismuth

The {0001}, {011̄2} and {112̄0} (respectively, the pseudo-cubic {111}, {100} and {110}) surface of Sb and Bi in the atomically clean state have been studied by low-energy electron diffraction. The {0001} and the {011̄2} surfaces have the ideal structure expected from simple termination of the bulk. The {112̄0} surfaces undergo reconstruction of the structure into superlattices which are different for Sb and for Bi. Oxygen adsorption experiments indicate that the {0001} surface is very inert and the {011̄2} noticeably more reactive, while the {112̄0} surface requires incubation before chemisorption occurs. Once started, the reaction proceeds very rapidly. These results can be qualitatively understood in terms of the "dangling" bond picture of ideal surfaces. The problem of structural reconstruction is discussed.