Corner hole adatom stacking fault structure of Bi on Au(1 1 1)

The surface atomic structure of Bi on Au(1 1 1) is studied with scanning tunneling microscopy. At about 0.5 monolayer of Bi, a well-ordered 6 × 6 atomic structure is observed. The structure has three notable features: corner holes, Bi adatoms, and stacking faults, very similar to a semiconductor surface of Si(1 1 1)-7 × 7. Out of 18 Bi surface atoms in a unit cell, six atoms are at hollow sites and are adatoms, and another six atoms are near-bridge sites. The last six atoms surround corner holes and are lower than other surface atoms by about 0.2 Å. A possible atomic model is proposed based on our observation.