Deep-going reconstruction of Ir(100)-5x1

We present a new investigation of the metastable 1x1 and reconstructed 5x1 phases of Ir(100) using quantitative low-energy electron diffraction and scanning tunnelling microscopy. It is shown that the 5x1 reconstruction of Ir(100) extends up to the fourth layer into the surface. This structural information is retrieved by the use of electron energies up to 600 eV which simultaneously provides an unusually broad database of more than 10.000 eV. Together with an excellent quality of the theory-experiment fit equivalent to an R-factor of RP=0.144 this allows for rather small error limits of the as many as 17 structural parameters describing the four-layer reconstructed surface. Similar features hold for the 1x1 phase which is analysed in parallel. In addition, we present a systematic investigation of the influence of the electron energy range applied and of the allowed depth of reconstruction on the accuracy of the analysis. It appears that for the case of Ir(100)-5x1 the structural parameters describing the top two layers are largely independent from the consideration of the reconstruction of deeper layers