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O: Oberflächenphysik

O 9: Rastersondentechniken I

O 9.4: Vortrag

Montag, 8. März 2004, 16:30–16:45, H36

Anisotropy of bulk band structure observed by electron scattering at subsurface impurities in Ag(111) — •A. Weismann, M. Wenderoth, N. Quaas, and R. G. Ulbrich — IV. Phys. Institut, Universität Göttingen, D-37075 Göttingen

Dilute magnetic alloys, prepared by co-deposition of Co and Ag on a Ag(111)-Surface (0,4% Co), are investigated by means of Scanning Tunnel Microscopy (STM) and spatially resolved Scanning Tunnel Spectroscopy (STS) at 8K. Single impurities lying shallow below the surface emerge in atomically resolved (111) surface topographies as complex structures on different length scales. By means of Fourier-transformed STM different scattering mechanisms can be extracted. Apart from the atomic lattice we observe the well known radially symmetric oscillations of the surface state. Additional oscillations with a much shorter wavelength and triangular shape can be observed. We attribute this pattern to the scattering of bulk electrons. The observed threefold symmetry reflects the symmetry of the fcc - Brillouinzone in (111)-direction. This work is supported by the DFG, SFB 602.