Tunneling conductance in topological insulator ferromagnet/dx2+y2+idxydx2+y2+idxy mixed wave superconductor junctions

• Using BTK theory studied tunneling conductance in TI-based FM/dx2+y2+idxydx2+y2+idxy S junctions.
• A clear difference in tunneling spectra between dx2−y2dx2−y2 and dx2−y2+idxydx2−y2+idxy-wave.
• In FM/dx2−y2+idxydx2−y2+idxy S junction, a dip structure appears at eV=±Δ2eV=±Δ2 for α=0.25πα=0.25π.
• The conductance depends on the magnetic gap, angle α  , and the ratio of Δ2/Δ1Δ2/Δ1.
• The result can be used to determine the magnitude of gaps and BTRS states pairing.

The tunneling conductance in a topological insulator (TI) ferromagnet/dx2−y2+idxydx2−y2+idxy mixed wave superconductor (FM/dx2−y2+idxydx2−y2+idxy S) junction is studied based on the Blonder–Tinkham–Klapwijk (BTK) theory. It is demonstrated that the conductance strongly depends on the magnetic gap, the superconducting pair symmetry orientation, and the magnitude of the ratio of Δ2/Δ1Δ2/Δ1. Here Δ1(Δ2)Δ1(Δ2) is the absolute pair potential of dx2−y2(dxy)dx2−y2(dxy) component. For a large magnetic gap, the tunneling spectrum is characterized by a dip structure. When α=0.25πα=0.25π, the conductance dip appears at eV=±Δ2eV=±Δ2. Thus, the dx2−y2+idxydx2−y2+idxy pairing symmetry as well as the magnitude of the gap can be determined from the experiment of scanning tunneling spectroscopy.