Probing Magnetic and Triplet Correlations in Spin-Split Superconductors with Magnetic Impurities
arXiv:2402.07184 · doi:10.1103/PhysRevResearch.6.033022
Abstract
A superconductor (SC) in proximity to a ferromagnetic insulator (FMI) is predicted to exhibit mixed singlet and triplet pair correlations. The magnetic proximity effect of FMI spin-splits the energy of Bogoliubov excitations and leads to a spin polarization at the surface for superconducting films thinner than the superconducting coherence length. In this work, we study manifestations of these phenomena in the properties of a magnetic impurity coupled via Kondo coupling to this FMI/SC system. Using the numerical renormalization group (NRG) method, we compute the properties of the ground state and low-lying excited states of a model that incorporates the Kondo interaction and a Ruderman-Kittel-Kasuya-Yosida (RKKY)-like interaction with the surface spin polarization. Our main finding is an energy splitting of the lowest even fermion-parity states caused by the proximity to the FMI. As the Kondo coupling increases, the splitting grows and saturates to a universal value equal to twice the exchange field of the FMI. We introduce a two-site model that can be solved analytically and provides a qualitative understanding of this and other NRG results. In addition, using perturbation theory we demonstrate that the mechanism behind the splitting involves the RKKY field and the triplet correlations of the spin-split superconductor. A scaling analysis combined with NRG shows that the splitting can be written as a single-parameter scaling function of the ratio of the Kondo temperature and the superconducting gap, which is also numerically obtained.
arXiv comment18 pages, 6 figures
References in corpus (43)
- Unpaired Majorana fermions in quantum wires
- Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
- Search for Majorana fermions in superconductors
- Odd Triplet Superconductivity and Related Phenomena in Superconductor-Ferromagnet Structures
- The numerical renormalization group method for quantum impurity systems
- Majorana Zero Modes and Topological Quantum Computation
- Spontaneously polarized half-gapped superconductivity
- Spin-resolved Andreev levels and parity crossings in hybrid superconductor-semiconductor nanostructures
- Isospin magnetism and spin-triplet superconductivity in Bernal bilayer graphene
- Triplet supercurrents in clean and disordered half-metallic ferromagnets
- Sum-rule Conserving Spectral Functions from the Numerical Renormalization Group
- End states and subgap structure in proximity-coupled chains of magnetic adatoms
- Probing Atomic Structure and Majorana Wavefunctions in Mono-Atomic Fe-chains on Superconducting Pb-Surface
- Kondo effect in a magnetic field and the magnetoresistivity of Kondo alloys
- Distinguishing a Majorana zero mode using spin resolved measurements
- Josephson Current through a correlated quantum level: Andreev states and Pi-junction behavior
- Single magnetic adsorbates on s-wave superconductors
- Colloquium: Nonequilibrium effects in superconductors with a spin-splitting field
- Induced Ferromagnetism due to Superconductivity in Superconductor-Ferromagnet structures
- Nontopological zero-bias peaks in full-shell nanowires induced by flux tunable Andreev states
- Direct manipulation of a superconducting spin qubit strongly coupled to a transmon qubit
- Shiba states and zero-bias anomalies in the hybrid normal-superconductor Anderson model
- Tuning Yu-Shiba-Rusinov States in a Quantum Dot
- Pairing symmetry conversion by spin-active interfaces in superconducting junctions
- Thermal, electric and spin transport in superconductor/ferromagnetic-insulator structures
- Majorana zero modes on a necklace
- Revealing the magnetic proximity effect in EuS/Al bilayers through superconducting tunneling spectroscopy
- Signature of odd-frequency pairing correlations induced by a magnetic interface
- Enhanced anti-ferromagnetic exchange between magnetic impurities in a superconducting host
- Spin screening of magnetic moments in superconductors
- Spin glass versus superconductivity
- Numerical renormalization group calculation of near-gap peaks in spectral functions of the Anderson model with superconducting leads
- Proximity-induced Shiba states in a molecular junction
- Spectroscopy of spin-split Andreev levels in a quantum dot with superconducting leads
- Yu-Shiba-Rusinov states in real metals
- Adaptive logarithmic discretization for numerical renormalization group methods
- Coexistence of superconductivity and spin-splitting fields in superconductor/ferromagnetic insulator bilayers of arbitrary thickness
- Quantum magnetism and topological superconductivity in Yu-Shiba-Rusinov chains
- Pair excitations of a quantum spin on a proximitized superconductor
- Magnetic impurities in spin-split superconductors
- Probing and dressing magnetic impurities in a superconductor
- Robust Spin Polarization of Yu-Shiba-Rusinov States in Superconductor/Ferromagnetic Insulator Heterostructures
- Anisotropy and spin-fluctuation effects on the spectral properties of Shiba impurities