Structural Examination of Au/Ge(001) by Surface X-Ray Diffraction and   Scanning Tunneling Microscopy
  The one-dimensional reconstruction of Au/Ge(001) was investigated by means of autocorrelation functions from surface x-ray diffraction (SXRD) and scanning tunneling microscopy (STM). Interatomic distances found in the SXRD-Patterson map are substantiated by results from STM. The Au coverage, recently determined to be 3/4 of a monolayer of gold, together with SXRD leads to three non-equivalent positions for Au within the c(8x2) unit cell. Combined with structural information from STM topography and line profiling, two building blocks are identified: Au-Ge hetero-dimers within the top wire architecture and Au homo-dimers within the trenches. The incorporation of both components is discussed using density functional theory and model based Patterson maps by substituting Germanium atoms of the reconstructed Ge(001) surface. 
S. Meyer, T. Umbach, C. Blumenstein, J. Sch\"afer, R. Claessen, S.   Sauer, S. J. Leake, P. R. Willmott, M. Fiedler, and F. ...
cond-mat.str-el cond-mat.mtrl-sci