Abstract
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/f-wave superconductor(TI-based FM/f-wave SC)tunnel structure is theoretically studied.Two symmetries of f1 and f2 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 retro-reflection 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.
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