# Enhanced Antiferromagnetic Exchange between Magnetic Impurities in a Superconducting Host

 Title: Enhanced Antiferromagnetic Exchange between Magnetic Impurities in a Superconducting Host Author: Yao, Norman Ying; Glazman, Leonid I; Demler, Eugene A.; Lukin, Mikhail D.; Sau, Jay D. Note: Order does not necessarily reflect citation order of authors. Citation: Yao, N. Y., L. I. Glazman, E. A. Demler, M. D. Lukin, and J. D. Sau. 2014. “Enhanced Antiferromagnetic Exchange Between Magnetic Impurities in a Superconducting Host.” Physical Review Letters 113 (8) (August). doi:10.1103/physrevlett.113.087202. Full Text & Related Files: Yao_EnhancedAntiferromagnetic.pdf (905.4Kb; PDF) Abstract: It is generally believed that superconductivity only weakly affects the indirect exchange between magnetic impurities. If the distance r between impurities is smaller than than the superconducting coherence length $$(r \lesssim \xi)$$ , this exchange is thought to be dominated by RKKY interactions, identical to the those in a normal metallic host. This perception is based on a perturbative treatment of the exchange interaction. Here, we provide a non-perturbative analysis and demonstrate that the presence of Yu-Shiba-Rusinov bound states induces a strong $$1/r^2$$ anti-ferromagnetic interaction that can dominate over conventional RKKY even at distances significantly smaller than the coherence length $$(r\ll \xi )$$. Experimental signatures, implications and applications are discussed. Published Version: doi:10.1103/PhysRevLett.113.087202 Other Sources: http://arxiv.org/abs/1309.2633 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:13421142 Downloads of this work: