Andreev bound states in ferromagnet-superconductor nanostructures

Abstract

We discuss the properties of a ferromagnet - superconductor heterostructure on the basis of a Hubbard model featuring exchange splitting in the ferromagnet and electron - electron attraction in the superconductor. We have solved the spin - polarized Hartree - Fock - Gorkov equations together with the Maxwell's equation (Ampere's law) fully self-consistently. We have found that a Proximity Effect - Fulde - Ferrell - Larkin - Ovchinnikov state is realized in such a heterostructure. It manifests itself in an oscillatory behavior of the pairing amplitude in the ferromagnet and spontaneously generated spin polarized current in the ground state. We argue that it is built up from the Andreev bound states, whose energy can be tuned by the exchange splitting and hence can coincide with the Fermi energy giving rise to a current carrying $\pi$-state. We also suggest experiments to verify these predictions.

arXiv comment12 pages, 5 figures included; to be published in Physica C

References in corpus (7)

• Coupling of two superconductors through a ferromagnet : evidence for a pi-junction
• Andreev Reflection In Ferromagnet-Superconductor Junctions
• Andreev bound states in high-$T_c$ superconducting junctions
• Phase coherent transport in hybrid superconducting nanostructures
• Proximity effects at ferromagnet-superconductor interfaces
• Oscillations of Andreev states in clean ferromagnetic films
• Chiral Loops and Ghost States in the Quenched Scalar Propagator

Cited by in corpus (6)

• Ferromagnet-Superconductor Hybrids
• Effects of spin-orbit interaction on superconductor-ferromagnet heterostructures: spontaneous electric and spin surface currents
• Orientation-dependent transport in junctions formed by $d$-wave altermagnets and $d$-wave superconductors
• Proximity effect in ferromagnet-superconductor hybrid structures: role of the pairing symmetry
• Origin of Spontaneous Currents in a Superconductor-Ferromagnet Proximity System
• Residual Kondo effect in quantum dot coupled to half-metallic ferromagnets