2006 Volume 4 Pages 435-438
We investigated the phase transition from a 3 × 3 to √3 × √3 structure on the Sn/Ge(111) surface at 220 K using a reflection high-energy positron diffraction. We measured the rocking curves at 110 K and 293 K under the one-beam condition and along the [11-2] and [10-1] directions. There are no significant changes in the rocking curves at any conditions according to the phase transition. The curves at both temperatures can be explained by ’one-up and two-down’ model for Sn atoms. The result clearly indicates the order-disorder phase transition. [DOI: 10.1380/ejssnt.2006.435]