Josephson current in strongly correlated double quantum dots

Abstract

We study the transport properties of a serial double quantum dot (DQD) coupled to two superconducting leads, focusing on the Josephson current through the DQD and the associated 0-$\pi$ transitions which result from the subtle interplay between the superconductivity, the Kondo physics, and the inter-dot superexchange interaction. We examine the competition between the superconductivity and the Kondo physics by tuning the relative strength $\Delta /T_K$ of the superconducting gap $\Delta$ and the Kondo temperature $T_K$, for different strengths of the superexchange coupling determined by the interdot tunneling $t$ relative to the dot level broadening $\Gamma$. We find strong renormalization of $t$, a significant role of the superexchange coupling $J$, and a rich phase diagram of the 0 and $\pi$-junction regimes. In particular, when both the superconductivity and the exchange interaction are in close competion with the Kondo physics ($\Delta \sim J\sim T_K$), there appears an island of ${\pi }^{\prime }$-phase at large values of the superconducting phase difference.

4 pages, 4 figures

References in corpus (7)

• Energy resolution and discretization artefacts in the numerical renormalization group
• Critical Current 0-$\pi$ Transition in Designed Josephson Quantum Dot Junctions
• Josephson current through a single Anderson impurity coupled to BCS leads
• Kondo-Enhanced Andreev Tunneling in InAs Nanowire Quantum Dots
• Superconductivity-enhanced bias spectroscopy in carbon nanotube quantum dots
• Interplay between Josephson effect and magnetic interactions in double quantum dots
• Josephson-current induced conformational switching of a molecular quantum dot

Cited by in corpus (1)

• Magnetic anisotropy effects on quantum impurities in superconducting host