Excess Kondo resonance in a quantum dot device with normal and superconducting leads: the physics of Andreev-normal co-tunneling.
We report on a novel Kondo phenomenon of interacting quantum dots coupled asymmetrically to a normal and a superconducting lead. The effects of intradot Coulomb interaction and Andreev tunneling give rise to Andreev bound resonances. As a result, a new type of co-tunneling process, which we term Andreev-normal co-tunneling, is predicted. At low temperatures, coherent superposition of these co-tunneling processes induces a Kondo effect in which Cooper pairs directly participate formation of a spin singlet, leading to four Kondo resonance peaks in the local density of states, and enhancing the tunneling current.
Sun
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Center for the Physics of Materials and Department of Physics, McGill University, Montreal, PQ, Canada H3A 2T8.
Guo
H
H
Lin
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TH