Steps on Si(001)

Abstract

Steps on vicinal Si(001) are either one or two atomic layers high. When the tilt of the surface about [11̄0] is 2°, alternating type-A and type-B single steps dominate. When the tilt angle is increased to 4°, the steps combine to form straight, evenly spaced type-B double steps. Type-A double steps do not occur. At kinks the double steps split into single steps. Tunneling images of the double steps reveal the rebonded atoms described by the Chadi model.