We consider two-dimensional superconductor/ferromagnet/superconductor junctions, and we investigate the subgap modes along the junction interface. The subgap modes exhibit characteristics similar to the Yu-Shiba-Rusinov states that originate from the interplay between superconductivity and ferromagnetism in the magnetic junction. The dispersion relation of the subgap modes shows qualitatively different profiles depending on the transport state (metallic, half-metallic, or insulating) of the ferromagnet. As the spin splitting in the ferromagnet is increased, the subgap modes bring about a 0-π transition in the Josephson current across the junction, with the Josephson current density depending strongly on the momentum along the junction interface (i.e., the direction of the incident current). For clean superconductor-ferromagnet interfaces (i.e., strong coupling between superconductors and ferromagnet), the subgap modes develop flat quasiparticle bands that allow us to engineer the wave functions of the subgap modes along an inhomogeneous magnetic junction.
Bibliographical noteFunding Information:
Y.F. acknowledges support from the National Natural Science Foundation of China (Grant No. 12005011). S.C. acknowledges support from the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301602), the National Science Association Funds (Grant No. U2230402), and the National Natural Science Foundation of China (Grants No. 11974040 and No. 12150610464). S.H. and M.-S.C. were supported by the Ministry of Science and ICT of Korea (Grants No. 2017R1E1A1A03070681 and No. 2022M3H3A1063074) and by the Ministry of Education of Korea through the BK21 program.
© 2023 American Physical Society.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics