It is generally believed that superconductivity only weakly affects the indirect exchange between magnetic impurities. If the distance r between impurities is smaller than the superconducting coherence length (![]()
), this exchange is thought to be dominated by RKKY interactions, identical to those in a normal metallic host. This perception is based on a perturbative treatment of the exchange interaction. In our study, we provided a non-perturbative analysis and demonstrated that the presence of Yu-Shiba-Rusinov bound states induced a strong 1/r2 anti-ferromagnetic interaction that could dominate over conventional RKKY even at distances significantly smaller than the coherence length (![]()
). Experimental signatures, implications and applications were discussed.
