Correlated electron transport through double quantum dots coupled to normal and superconducting leads

Abstract

We study Andreev transport through double quantum dots connected in series normal and superconducting (SC) leads, using the numerical renormalization group. The ground state of this system shows a crossover between a local Cooper-pairing singlet state and a Kondo singlet state, which is caused by the competition between the Coulomb interaction and the SC proximity. We show that the ground-state properties reflect this crossover especially for small values of the inter-dot coupling $t$, while in the opposite case, for large $t$, another singlet with an inter-dot character becomes dominant. We find that the conductance for the local SC singlet state has a peak with the unitary-limit value $4e^2/h$. In contrast, the Andreev reflection is suppressed in the Kondo regime by the Coulomb interaction. Furthermore, the conductance has two successive peaks in the transient region of the crossover. It is further elucidated that the gate voltage gives a different variation into the crossover. Specifically, as the energy level of the dot that is coupled to the normal lead varies, the Kondo screening cloud is deformed to a long-range singlet bond.

11 pages, 10 figures

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Cited by in corpus (20)

• Josephson and Andreev transport through quantum dots
• Superconducting proximity effect in interacting double-dot systems
• Josephson current in strongly correlated double quantum dots
• Fano-type interference in quantum dots coupled between metallic and superconducting leads
• Interplay between Kondo and Andreev-Josephson effects in a quantum dot coupled to one normal and two superconducting leads
• Interplay between direct and crossed Andreev reflections in hybrid nano-structures
• Local and non-local thermopowers in three-terminal nanostructures
• Decoherence effect on the Fano lineshapes in double quantum dots coupled between normal and superconducting leads
• Evidence of Andreev blockade in a double quantum dot coupled to a superconductor
• Kondo physics in double quantum dot based Cooper pair splitters
• Non-hermitian topology in multiterminal superconducting junctions
• Coulomb blockade and Kondo effect in the electronic structure of Hubbard molecules connected to metallic leads: a finite-temperature exact-diagonalization study
• Splitting efficiency and interference effects in a Cooper pair splitter based on a triple quantum dot with ferromagnetic contacts
• Anomalous Fano Resonance in Double Quantum Dot System Coupled to Superconductor
• Transient effects in double quantum dot sandwiched laterally between superconducting and metallic leads
• Replicas of the Fano resonances induced by phonons in a subgap Andreev tunneling
• Subgap dynamics of double quantum dot coupled between superconducting and normal leads
• Lasing in a coupled hybrid double quantum dot-resonator system
• Theory of Andreev Blockade in a Double Quantum Dot with a Superconducting Lead
• Transient triplet blockade in Andreev junction