2006/05/31 by Colin Benjamin, Thibaut Jonckheere, Alex Zazunov +2 · 1 citation
Engineering · Physics and Astronomy · #Bistability #Bound state #Condensed matter physics #Josephson effect #Molecular Junctions and Nanostructures #Physics #Physics of Superconductivity and Magnetism #Pi Josephson junction #Position (finance) #Quantum #Quantum and electron transport phenomena #Quantum dot #Quantum mechanics #Qubit #Spin (aerodynamics) #Superconductivity #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1140/epjb/e2007-00167-6
published as European Physical Journal B 57 (13/06/2007) 279-289
openalex publication_date 2007/06/01 · arxiv created 2007/07/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider a model for a single molecule with a large frozen spin sandwiched in between two BCS superconductors at equilibrium, and show that this system has a π junction behavior at low temperature. The π shift can be reversed by varying the other parameters of the system, e.g., temperature or the position of the quantum dot level, implying a controllable π junction with novel application as a Josephson current switch. We show that the mechanism leading to the π shift can be explained simply in terms of the contributions of the Andreev bound states and of the continuum of states above the superconducting gap. The free energy for certain configuration of parameters shows a bistable nature, which is a necessary pre-condition for achievement of a qubit.