Superconducting Proximity Effect in Quantum Dots
Final Report Abstract
Well-defined and -controllable nanostructures such as quantum dots are ideal model systems to investigate the interplay of Coulomb interaction, nonequilibrium, and collective order. We study theoretically electronic transport through systems containing interacting quantum dots coupled to superconducting leads. Superconducting correlations are induced on the quantum dots by the equilibrium and nonequilibrium proximity effect and can be manipulated via gate and bias voltages. They affect the transport characteristics, e.g., of the Josephson or the local and the nonlocal Andreev currents. For hybrid systems involving noncollinear magnetism, unconventional superconducting pairing can be induced. Superconducting correlations can also be probed by analyzing the full counting statistics obtained by a time-resolved detection of individual electron-tunneling events. The main objective of the project was to develop and apply theoretical tools that properly take into account the important role played by Coulomb interaction in the quantum dot. On the one hand, we did this based on a diagrammatic real-time technique. On the other hand, we employed the numerically demanding ISPI scheme. We identified for various device geometries signatures of the induced conventional and unconventional superconducting correlations in transport quantities such as the current, the current noise, and higher-order factorial cumulants of the full counting statistics.
Publications
- Iterative path-integral summations for the tunneling magnetoresistance in interacting quantum-dot spin valves
S. Mundinar, P. Stegmann, J. König, and S. Weiss
(See online at https://doi.org/10.1103/PhysRevB.99.195457) - Driven Superconducting Proximity Effect in Interacting Quantum Dots. Phys. Rev. B 85, 094518 (2012)
A.G. Moghaddam, M. Governale, and J. König
(See online at https://doi.org/10.1103/PhysRevB.85.094518) - Iterative path integral summation for nonequilibrium quantum transport. Phys. Status Solidi B 250, 2298 (2013)
S. Weiss, R. Hützen, D. Becker, J. Eckel, R. Egger, and M. Thorwart
(See online at https://doi.org/10.1002/pssb.201349187) - Josephson-Majorana Cycle in Topological Single-Electron Hybrid Transistors. Phys. Rev. B 88, 024512 (2013)
N. Didier, M. Gibertini, A.G. Moghaddam, J. König, and R. Fazio
(See online at https://doi.org/10.1103/PhysRevB.88.024512) - Renormalization Effects in Interacting Quantum Dots Coupled to Superconducting Leads. Phys. Rev. B 87, 014509 (2013)
D. Futterer, J. Swiebodzinski, M. Governale, and J. König
(See online at https://doi.org/10.1103/PhysRevB.87.014509) - Unconventional Superconductivity in Double Quantum Dots. Phys. Rev. B 90, 220501(R) (2014)
B. Sothmann, S. Weiss, M. Governale, and J. König
(See online at https://doi.org/10.1103/PhysRevB.90.220501) - Detection of interactions via generalized factorial cumulants in systems in and out of equilibrium. Phys. Rev. B 92, 155413 (2015)
P. Stegmann, B. Sothmann, A. Hucht, and J. König
(See online at https://doi.org/10.1103/PhysRevB.92.155413) - Odd-triplet superconductivity in single-level quantum dots. Phys. Rev. B 96, 064529 (2017)
S. Weiss and J. König
(See online at https://doi.org/10.1103/PhysRevB.96.064529) - Coherent dynamics in stochastic systems revealed by full counting statistics. Phys. Rev. B 98, 035409 (2018)
P. Stegmann, J. König, and S. Weiss
(See online at https://doi.org/10.1103/PhysRevB.98.035409) - Revealing attractive electron-electron interaction in quantum dots by full counting statistics. New J. Phys. 20, 073023 (2018)
E. Kleinherbers, P. Stegmann, and J. König
(See online at https://doi.org/10.1088/1367-2630/aad14a)
