Minigap, parity effect, and persistent currents in SNS nanorings

Article

关键词: METAL;    SUPERCONDUCTOR;    JUNCTIONS;    SUPERCURRENT;    DENSITY;    LENGTH;    STATES;   

DOI  :  10.1103/PhysRevB.74.184502

来源: SCIE

【 摘 要 】

We have evaluated a proximity-induced minigap in the density of states (DOS) of SNS junctions and SNS nanorings at an arbitrary concentration of nonmagnetic impurities. We have demonstrated that an isotropic energy minigap in the electron spectrum opens up already at arbitrarily weak disorder, while the angle-resolved DOS at higher energies can remain strongly anisotropic. The minigap value epsilon(g) can be tuned by passing a supercurrent through an SNS junction or by applying a magnetic flux Phi to an SNS ring. A nonmonotonous dependence of epsilon(g) on Phi has been found at weak disorder. We have also studied persistent currents in isolated SNS nanorings. For an odd number of electrons in the ring we have found a nontrivial current-phase (current-flux) relation which, at relatively high disorder, may lead to a pi-junction state and spontaneous currents in the ground state of the system.

【 授权许可】

Free