Supergap anomalies in cotunneling between normal-superconducting and between two superconducting leads via a small quantum dot

2008/02/05 by V. V. Mkhitaryan, M. E. Raikh, M. É. Raǐkh · 5 citations
Physics and Astronomy · #Condensed matter physics #Coulomb #Density of states #Electron #Energy (signal processing) #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Quasiparticle #Superconductivity #Superconductivity in MgB2 and Alloys #cond-mat.mes-hall #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevb.77.195329

published in Physical Review B 77(19) (American Physical Society) · 11 pages, 7 figures

arxiv created 2008/02/05 · openalex publication_date 2008/05/29 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

Cotunneling current through a resonant level coupled to either normal and superconducting or to two superconducting leads is studied for the domain of bias voltages V, exceeding the superconducting gap 2\ensuremathΔ. Due to the on-site repulsion in the resonant level, cotunneling of an electron is accompanied by the creation of a quasiparticle in a superconducting lead. Energy conservation imposes a threshold for this inelastic transport channel: V_c=3\ensuremathΔ for normal-superconductor case and \stackrel\ifmmode \else \~\fiV_c=4\ensuremathΔ for the superconductor-superconductor (S-S) case. We demonstrate that the behavior of the current near the respective thresholds is nonanalytic, namely, \ensuremathδIⁱⁿ(V)\ensuremath∝(V\ensuremath-V_c)^3/2\ensuremathΘ(V\ensuremath-V_c) and \ensuremathδIⁱⁿ(V)\ensuremath∝(V\ensuremath-\stackrel\ifmmode \else \~\fiV_c)\ensuremathΘ(V\ensuremath-\stackrel\ifmmode \else \~\fiV_c). Stronger anomaly for the S-S leads is the consequence of the enhanced density of states at the edges of the gap. In addition, the enhanced density of states makes the threshold anomalies for two-electron cotunneling processes in the Coulomb-blockaded regions more pronounced than for the normal-normal leads.

Citations

• Even-Odd Effect in Andreev Transport through a Carbon Nanotube Quantum Dot
• Josephson Transport through a Hubbard Impurity Center
• Inelastic Electron Tunneling via Molecular Vibrations in Single-Molecule Transistors
• Kondo effect and Josephson current through a quantum dot between two superconductors
• Interference of two electrons entering a superconductor
• Nonequilibrium Dynamics of Andreev States in the Kondo Regime
• Multiple Andreev Reflections in a Carbon Nanotube Quantum Dot
• Quantum Dot in the Kondo Regime Coupled to Superconductors
• 3etunneling processes in a superconducting single-electron tunneling transistor