Quantum Processes in Josephson Junctions and Weak Links

Center for Materials Science Colloquium, Los Alamos National Laboratory Institute for Materials Science, Los Alamos National Laboratory

Speaker: J. A. Sauls
Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208
December 9, 2015

Abstract: I discuss the theory of transport in Superconducting Josephson point contacts and weak links. Andreev bound states, multiple Andreev reflection and Spin Mixing (unitary spin dynamics induced by the SF interface) lead to unique signatures in the transport of charge, energy and spin in these devices. I illustrate these processes with three examples: (i) resonant heat transport, (ii) resonant spin transport in SFS junctions and (iii) long-range spin-transfer torques in coupled SFNFS devices. The latter could provide the basic element for constructing a new class of spintronic devices with quantum control.

This research was supported by NSF Grant: DMR-1106315.

Slides: [PDF]

Presentation based on these Research Papers:

  1. Heat Transport Through Josephson Point Contacts, Erhai Zhao, Tomas Löfwander and J. A. Sauls Phys. Rev. B 69, 134503 (2004)
  2. Phase Modulated Thermal Conductance of Josephson Weak Links, Erhai Zhao, Tomas Löfwander and J. A. Sauls, Phys. Rev. Lett. 91, 077003 (2003)
  3. Dynamics of spin transport in voltage-biased Josephson junctions, Erhai Zhao and J. A. Sauls, Phys. Rev. Lett. 98, 206601 (2007)
  4. Theory of Nonequilibrium Spin Transport and Spin Transfer Torque in Superconducting-Ferromagnetic Nanostructures, Erhai Zhao and J. A. Sauls, Phys. Rev. B 78, 174511 (2008)

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