Interplay between magnetic gap and quasiparticle lifetime in topological insulator ferromagnet/f-wave superconductor junctions

Using the modified Blonder-Tinkham-Klapwijk(BTK)theory,the interplay between the lifetime of quasi particles and the magnetic gap in a topological insulator-based ferromagnet/fwave superconductor(TI-based FM/f-wave SC)tunnel structure is theoretically studied.Two symmetries of f_(1) and f_(2) waves are considered for superconducting pairing states.The results indicate that reducing the finite quasi-particle lifetime will induce a transformation of energy-gap peaks into a zero-bias peak in tunneling conductance spectrum,as well as a transformation of energy-gap dips into a zero-bias dip in shot noise spectrum,ultimately resulting in the smoothing of the zero-bias conductance peak and the zero-bias shot noise dip.An increase in magnetic gap will suppress the tunnel conductance and shot noise when the conventional Andreev retroreflection dominates,but will enhance them when the specular Andreev reflection is dominant.Both specular Andreev reflection and conventional Andreev retro-reflection will be enhanced as the quasi-particle lifetime increases.When Fermi energy equals the magnetic gap,shot noise and tunneling conductance vanish across all energy ranges.These findings not only contribute to a better understanding of specular Andreev reflection in the FM/f-wave SC junction based on TIs but also provide insights for experimentally determining the f-wave pairing symmetry.