Tunneling spectra for quantum wire/iron-based superconductor junction

Abstract

Taking into account the interface scattering effect on each band (in-band interaction) and the interaction between the bands (inter-band interaction), within an extended Blonder-Tinkham-Klapwijk scattering formalism, we have studied the quasi-particle transport coefficients and the tunneling spectrum for quantum wire/iron-based superconductor junction of different types of two-level system by solving the Bogoliubov-de Gennes equations. It has been shown that: 1) When the junction is in ballistic limit, the platform near zero bias of the s -wave tunneling spectroscopy will become a conductance peak as the inter-band interaction increases, while a dip occurs in s++ -wave tunneling spectroscopy, and the zero-bias conductance peak will be depressed for p-wave. 2) When the interface scattering effect is not zero, the peaks in the two energy gaps of both s -wave and s++ -wave iron-based superconductor will be depressed; as the inter-band interaction increases, the dip between the two peaks will increase, moreover, the value of zero-bias conductance peaks for p-wave will be lowered and the value of nonzero-bias conductance will be increased. 3) As the in-band interaction is increased, the self-conductance peak will become sharper, while the another conductance peak is not only lowered but also smoothed. These results will be helpful for clarifying the structure of the pair-potential in iron-based superconductor and distinguishing their types.