Structure analysis of Ge(111)11-H by low-energy electron diffraction

The relaxation of the outermost Ge layers of the H-terminated Ge(111) surface is determined via low-energy electron diffraction intensity analysis. A contraction of the first interlayer spacing $d_{12}$ by 0.10±0.05 Å and a possible expansion of the second interlayer spacing $d_{23}$ by 0.05±0.05 Å is found. The influence of the H on the intensity curves is calculated and found to be negligible. A comparison with first-principles calculations is made and a mechanism is discussed that may explain the relaxation.