The results of the first totally ab initio calculation of the energy of a Takayanagi reconstruction, the 3 x 3 reconstruction on the Ge(111) surface, were presented. The energies of a number of elements of the Takayanagi reconstruction including the 3 x 3 structure without adatoms have also been calculated and the results were used to obtain information about the microscopic mechanism that was responsible for stabilising the Takayanagi structure. It was found that the addition of adatoms to form the complete Takayanagi structure led to a large reduction in the energy of the surface and so it could be concluded that the adatoms play a crucial role in stabilising the Takayanagi reconstruction. The reduction in energy was attributed to a lowering of the surface stress.

An ab initio Investigation of the Takayanagi Reconstruction. M.C.Payne: Journal of Physics C, 1987, 20[36], L983-7