Point-Contact Spectroscopy
A.G.M. Jansen
Max-Planck-Institut für Festkörperforschung, Hochfeld-Magnetlabor, B.P.166, 38042 Grenoble Cedex 9, France
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In a small metallic constriction ("point contact") the transport of electrons is ballistic. The applied voltage V tunes a well-defined non-equilibrium energy eV of electrons. The nonlinear current-voltage characteristics can be used to perform energy-resolved spectroscopy of the inelastic scattering of electrons with elementary excitations in metal (e.g. phonons, magnons, crystal-field levels, paramagnetic impurities). The basic elements of the point--contact method and its applications will be discussed. In recent point-contact experiments the observed phenomena (weak localization, resistance fluctuations) need a description that goes beyond the classical Boltzmann approach of electronic transport in a point contact. In analogy to observed effects in the diffusive transport in mesoscopic systems, these phenomena are explained by considering quantum-interference effects in the ballistic transport near the contact region related to the wave character of the electrons.
DOI: 10.12693/APhysPolA.82.539
PACS numbers: 72.10.-d, 73.40.Jn