GE(113) RECONSTRUCTION STABILIZED BY SUBSURFACE INTERSTITIALS - AN X-RAY-DIFFRACTION STRUCTURE-ANALYSIS

The three-dimensional atomic coordinates of the Ge(113)-(3 X 1) surfac e have been determined by analyzing in-plane and out-of-plane x-ray in tensity data. Besides dimer and adatom motifs, which reduce the number of dangling bonds, a random distribution of subsurface interstitials has been identified. Subsurface interstitials relieve elastic stress a nd lower the energy of the electronic system. Together with the delica te balance between the energy gain due to reduction of dangling bonds and the energy costs due to induced strain this determines the nature of the (3 X 1) reconstruction of Ge(113).