Renormalization approach to the superconducting Kondo model

Abstract

An approach to bound states based on unitary transformations of Hamiltonians is presented. The method is applied to study the interaction between electrons in a BCS $s$-wave superconductor and a quantum spin. It is shown that known results from the t-matrix method and numerical studies are reproduced by this new method. As a main advantage, the method can straightforwardly be extended to study the topological properties of combined bound states in chains of many magnetic impurities. It also provides a uniform picture of the interplay between the Yu-Shiba-Rusinov (YSR) bound states and the Kondo singlet state.

29 pages, 7 figures, Submission to SciPost

References in corpus (7)

• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Spectral properties of locally correlated electrons in a BCS superconductor
• Topological Superconductivity induced by Ferromagnetic Metal Chains
• Electron Cotunneling into a Kondo Lattice
• Scaling of Yu-Shiba-Rusinov energies in the weak-coupling Kondo regime
• The Andreev states of a superconducting quantum dot: mean field vs exact numerical results
• Temperature-dependent spectral function of a Kondo impurity in an $s$-wave superconductor