The reconstruction of the Ir(100) surface as well as the transition of the regular bulk-like structure into the reconstructed phase by thermal activation at >800K was observed in a field-ion microscope. The field-ion microscope image of the thermally stable reconstructed surface supports the rippled quasi-hexagonal structure model for Ir(100) (1 x 5) already developed from low-energy electron diffraction structure analyses.

Evidence for the Ir(100) Surface Reconstruction by Field-Ion Microscopy. J.Witt, K.Müller: Physical Review Letters, 1986, 57, 1153-6