Determination of the (3 x 3)-Sn/Ge(111) structure by photoelectron diffraction - art. no. 115406

The bonding geometry of Sn on Ge(111) has been quantitatively determined fo r the (3 X 3) phase at 150 K. Energy scan photoelectron diffraction of the Sn 4d core levels has been used to independently measure the bond length be tween Sn and its nearest-neighbor Ge atoms and the vertical distance betwee n Sn and the Ge atom beneath. This latter distance is found to be similar t o0.3 Angstrom larger for one Sn atom out of the three contained in the latt ice unit cell. The bond lengths and the bond directions, obtained by the an gular scans, are found to be practically the same for the three Sn atoms wi thin +/-0.03 Angstrom and +/-3 degrees, respectively. The three nearest-nei ghbor Ge atoms thus partially follow the Sn atom in its vertical ripple.