Super-Spintronics

Wolfgang Belzig

Universität Konstanz

Nanostructures of superconductors and magnets are interesting for fundamental and applied physics. At first sight, Cooper pairing in singlets is incompatible with a spin polarization. However, this competition can be utilized to manipulate the superconducting and magnetic properties in mesoscopic structures. One paradigm is a so-called pi-Josephson junction with the spectacular reversal of the supercurrent through a magnetic metal, which was recently observed experimentally and has possible applications in quantum computing. Another example is the fundamental problem of a supercurrent through a single-level quantum dot. The interplay between charge quantization and Kondo correlations is visible as pi-0 transition in the current-phase relation.