Coherent conductance and magnetoresistance in a topological insulator ferromagnet/superconductor/ferromagnet junction

• Using BTK formalism studied coherent conductance and magnetoresistance in a TI-based F/SC/F junction.
• Due to the effect of perpendicular magnetization on the TI surface spin eigenstates, there exist a large difference between parallel and antiparallel conductances.
• We find that both the parallel and antiparallel conductances and magnetoresistance oscillate as a function of gate voltage exerted on the superconductor layer.

We investigate theoretically the coherent conductance and magnetoresistance in a topological insulator ferromagnet/superconductor/ferromagnet (F/SC/F) junction with perpendicular magnetization. It is shown that there exists a large difference between the coherent conductance of the parallel and antiparallel magnetization configurations, which leads to a large magnetoresistance. The superconductor layer thickness dependence of the magnetoresistance is discussed in terms of the contributions of the local Andreev reflection, electron elastic cotunneling and crossed Andreev reflection to the parallel and antiparallel conductances.