Yu-Shiba-Rusinov bound states boost odd-frequency superconductivity

Abstract

We predict that the occurence of zero energy Yu-Shiba-Rusinov(YSR) bound states in two different setups, metal-spin flipper-metal-s-wave superconductor ($N_{1}-sf-N_{2}-S$) and superconductor-metal-spin flipper-metal-superconductor ($S-N_{1}-sf-N_{2}-S$) junctions, can generate multi-fold enhancement of surface-induced odd-frequency superconductivity. On the other hand, in the absence of these bound states, even-frequency superconductivity dominates. Specifically, in a $S-N_{1}-sf-N_{2}-S$ Josephson junction, the emergence of zero energy YSR bound states leads to a $0-\pi$ junction transition and surface odd-frequency superconductivity dominance. Notably, odd-frequency superconductivity vanishes in the absence of YSR-bound states. Interestingly, the equal spin-triplet pairing is the dominant component in the surface induced odd-frequency superconductivity in both setups, which could have important implications for superconducting spintronics. Overall, our findings may help to detect the presence of YSR-bound states through the observation of surface induced odd-frequency superconductivity and contribute to a better understanding of their relationship.