Monatomic steps on the InAs(110) surface

Three types of monatomic steps are observed on the (110) cleavage surface of InAs, with edges parallel to the (110), (111), and (112) directions. The (110)-type steps have unserrated edges, but the (111) and (112) step edges are sometimes serrated, with periodicities of 9.8±{}0.8 and 6.7±{}0.8 A{}, respectively. Models of all three step types are presented: the edges of the (110) steps are unserrated because no new dangling bonds are introduced by such steps; the serrated (111) and (112) step edges are associated with dimerization of surface anions.