Ordering of subsurface interstitial atoms in the Ge(113) surface studied by SPA-LEED

The surface order of the reconstructed Ge(113)-(3 x 2) phase was investigat ed by SPA-LEED (Spot Profile Analysis Low Energy Electron Diffraction). The LEED pattern exhibits very sharp (3 x 1) spots and broadened (3 x 2) spots which can be traced back to a disordered phase of interstitial atoms. At t emperatures below 370 K, the (3 x 2) spots are split in the [1 (1) over bar 0] direction. A quantitative determination of the domain size distribution s with the domain matrix method reveals that the split profiles can be expl ained with a non-geometrical distribution of (3 x 2) domains separated by a ntiphase domain boundaries. This may indicate a relief of surface stress at antiphase domain boundaries in the [1 (1) over bar 0] direction. Thereby, a fraction of 70 +/- 13% of the surface is covered with (3 x 2) domains, wh ile the remaining part consists of domain boundaries and (3 x 1) domains. F or temperatures above 370 K, a splitting of the (3 x 2) spots is not observ ed, and the domain size distributions are geometric. (C) 1999 Elsevier Scie nce B.V. All rights reserved.