Scanning Tunneling Microscopy and Spectroscopy of Aluminum based Quasicrystals and Approximants

On the nanometer scale, the local variation of the electronic density of states of aluminum based complex metallic alloys (quasicrystals and approximants) is experimentally investigated by low temperature scanning tunneling spectroscopy. We report on the correlation between the local variations of the electronic density of states and the electrical resistivity. The surface structure is investigated by scanning tunneling microscopy, low energy electron diffraction, and X-ray photoemission diffraction. Experimental results are interpreted on the basis of the respective bulk structure models.