Nanoscopic Tunneling Contacts on Mesoscopic Multiprobe Conductors

We derive Bardeen-like expressions for the transmission probabilities between two multi-probe mesoscopic conductors coupled by a weak tunneling contact. We emphasize especially the dual role of a weak coupling contact as a current source and sink and analyze the magnetic field symmetry. In the limit of a point-like tunneling contact the transmission probability becomes a product of local, partial density of states of the two mesoscopic conductors. We present expressions for the partial density of states in terms of functional derivatives of the scattering matrix with respect to the local potential and in terms of wave functions. We discuss voltage measurements and resistance measurements in the transport state of conductors. We illustrate the theory for the simple case of a scatterer in an otherwise perfect wire. In particular, we investigate the development of the Hall-resistance as measured with weak coupling probes.Comment: 10 pages, 5 figures, revte

Theories and Applications of Multiple Scattering

We develop a theory for the scattering of surface electron off a step edge on (111) surface of fcc noble metals. By using multiple scattering theory, the scattering off a step edge can be characterized by a phase shift. This phase shift cannot be determined completely with the STM image near a step edge (by itself). However, by putting several Fe adatoms (with known phase shift) near the step edge, we can extract the information of the step edges phase shift. We suggest this as an experiment to study the scattering properties of the step edge