Quantum dot coupled to unconventional superconducting electrodes

Yshai Avishai^1,2,*, Tomosuke Aono¹, and Anatoly Golub¹

While Quantum dots connected on both sides to normal metallic leads is a central research topic in contemporary condensed matter physics, there is now a growing interest in the question of what happens if one or both leads are superconducting. In a series of papers we have developed a theoretical basis for the relevant physical situation. As it turn out, the resulting physical observables strongly depend on the symmetry of the superconducting electrodes order parameter. previously, we have studied the case of s-wave superconducting electrodes. Here, in this work, the physics of junctions containing p-wave superconducting and normal leads weakly coupled to an Anderson impurity in the Kondo regime is elucidated. For unconventional (unlike s wave) superconducting leads, mid-gap surface states play an important role in the tunneling process and help the formation of the Kondo resonance. The current, shot-noise power and Fano factor are calculated and displayed as functions of the applied voltage V in the sub-gap region eV < D (the superconducting gap). In addition, the Josephson current for a quantum dot in the Kondo regime weakly coupled on both sides to p-wave superconductors is computed as function of temperature and phase. The peculiar differences between the cases of s-wave and p-wave superconducting leads are pointed out.

PACS: 74.70.Kn, 72.15.Gd, 71.10.Hf, 74.20.Mn