Supraleitender Proximity-Effekt in Quantenpunkten
Zusammenfassung der Projektergebnisse
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.
Projektbezogene Publikationen (Auswahl)
- Iterative path-integral summations for the tunneling magnetoresistance in interacting quantum-dot spin valves
S. Mundinar, P. Stegmann, J. König, and S. Weiss
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter 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
(Siehe online unter https://doi.org/10.1088/1367-2630/aad14a)
