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Updated: May 25, 2026
05:39
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
Nonequilibrium transport through a spinful quantum dot with superconducting leads
B M Andersen1, K Flensberg, V Koerting
1Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark.
Physical Review Letters
|January 17, 2012
Summary
We investigated nonlinear cotunneling current in quantum dots. The study reveals how varying electrode coupling asymmetry influences current, leading to distinct transport mechanisms like multiple Andreev reflections and Yu-Shiba-Rusinov states.
Area of Science:
- Condensed Matter Physics
- Quantum Transport
Background:
- Quantum dots are crucial in nanoscale electronics.
- Superconducting leads enable unique quantum phenomena.
- Understanding transport mechanisms is key for quantum device development.
Purpose of the Study:
- To investigate nonlinear cotunneling current in a spinful quantum dot.
- To analyze the impact of electrode coupling asymmetry on current-voltage (IV) characteristics.
- To elucidate the interplay between different transport mechanisms.
Main Methods:
- Utilized a general nonequilibrium Green function formalism.
- Employed an effective Kondo model for theoretical analysis.
- Studied variations in IV characteristics with changing coupling asymmetry.
Main Results:
- Identified distinct current transport mechanisms based on coupling symmetry.
- Observed multiple Andreev reflections in the symmetric limit.
- Found spin-induced Yu-Shiba-Rusinov bound states in the asymmetric limit.
- Characterized a crossover regime with intermediate symmetry.
Conclusions:
- The interplay of transport mechanisms dictates IV characteristics.
- Results align with experimental observations of negative differential conductance.
- The study provides insights into subgap cotunneling spectroscopy.
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