The energies of the ideal (1 x 1), dimer (2 x 1) and trimer (3 x 1) structures on (001) surfaces were calculated by using MEAM for three diamond cubic crystals C, Si and Ge. From energy minimization, the dimer (2 x 1) and trimer (3 x 1) reconstructions could be formed naturally and without any barrier. The dimer corresponding to the lowest energy implies it was the easiest to be formed and the most stable as well. This was consistent with the experimental result and other theoretical prediction. Determined dimer bond length of 2.43Å for Si drops in the experimental range of 2.20 to 2.47Å, and of 2.5Å for Ge was close to the 2.55Å measured by X-ray diffraction. The trimer, constructed here firstly, had not been observed in the experimental due to its slightly higher energy than dimer. Its bond lengths were determined to be 1.96, 2.64 and 2.75Å for C, Si and Ge, respectively. Further experimental testing was needed.

Calculation of Surface Energy and Simulation of Reconstruction for Diamond Cubic Crystals (001) Surface. J.M.Zhang, H.Y.Li, K.W.Xu, V.Ji: Applied Surface Science, 2008, 254[13], 4128-33