Yu-Shiba-Rusinov states in real metals

摘要: Theoretical descriptions of Yu-Shiba-Rusinov (YSR) states induced by magnetic impurities inside the gap a superconductor typically rely on classical spin model or are restricted to spin-1/2 quantum spins. These models fail account for important aspects YSR transition-metal impurities, including effects higher spins coupled several conduction-electron channels, crystal ligand-field effects, and anisotropy. We introduce explore zero-bandwidth model, which incorporates these aspects, is readily solved numerically, analytically tractable in limiting cases. The principal simplification neglect Kondo renormalizations exchange couplings between impurity conduction electrons. Nevertheless, we find excellent correspondence those cases, can compare our results existing numerical-renormalization-group calculations. apply obtain understand phase diagrams as function pairing strength anisotropy well subgap excitation spectra. single-channel case most relevant embedded into metallic coordination complexes superconducting substrates, while multi-channel adatoms.