Point Contact Spectra on YBa2Cu3O7−x/La0.7Ca0.3MnO3bilayers

Point of Contact

Analysis of point-contact Andreev reflection spectra in spin polarization measurements

G. T. Woods,1,4 R. J. Soulen, Jr.,1 I. Mazin,1 B. Nadgorny,2 M. S. Osofsky,1 J. Sanders,3 H. Srikanth,3 W. F. Egelhoff,4 and R. Datla4 1Naval Research Laboratory, Washington, DC 20375, USA 2Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, USA 3Department of Physics, University of South Florida, Tampa, Florida 33620, USA 4National Institute of Standards and T...

Quantum point contact microscopy.

We introduce quantum point contact microscopy (QPCM) as a novel method for surface characterization, where the conductance through a quantum point contact formed by a metal atom between the tip of a scanning tunneling microscope and the surface is mapped across the surface. Application of QPCM to copper and gold (111) shows reproducibly atomic resolution, on gold (111) the alternating atomic st...

Role of critical current on the point-contact Andreev reflection spectra between a normal metal and a superconductor

The point-contact spectrum between a normal metal and a superconductor often shows unexpected sharp dips in the conductance at voltage values larger than the superconducting energy gap. These dips are not predicted in the Blonder-Tinkham-Klapwijk ~BTK! theory, commonly used to analyze these contacts. We present here a systematic study of these dips in a variety of contacts between different com...

Resonant multilead point-contact tunneling

We analyze a model of resonant point-contact tunneling between multiple Luttinger-liquid leads. The model is a variant of the multichannel Kondo model and can be related to the quantum Brownian motion of a particle on lattices with p flux through each plaquette ~in the three-lead case, it is a honeycomb lattice with p flux!. By comparing the perturbative and instanton gas expansions, we find a ...