Spin Polarized Current in the Ground State of Superconductor - Ferromagnet - Insulator Trilayers

TL;DR

This paper investigates the ground state properties of superconductor-ferromagnet-insulator trilayers, revealing that spontaneous spin-polarized currents can emerge due to Andreev bound states, with polarization influenced by band filling.

Contribution

It introduces a self-consistent theoretical framework combining Hubbard model and Maxwell's equations to analyze spin-polarized currents in trilayers, highlighting their dependence on exchange splitting and band filling.

Findings

Spontaneous spin-polarized currents occur at certain exchange splittings.

The current polarization depends strongly on band filling.

Andreev bound states are key to the current generation.

Abstract

We study the ground state properties of a superconductor - ferromagnet - insulator trilayer on the basis of a Hubbard Model featuring exchange splitting in the ferromagnet and electron - electron attraction in the superconductor. We solve the spin - polarized Hartree - Fock - Gorkov equations together with the Maxwell's equation (Ampere's law) fully self-consistently. For certain values of the exchange splitting we find that a spontaneous spin polarized current is generated in the ground state and is intimately related to Andreev bound states at the Fermi level. Moreover, the polarization of the current strongly depends on the band filling.