Theoretical Study of Tunneling Conductance in Normal-Metal/Insulator/PrOs$_{4}$Sb$_{12}$ and Ferromagnet/Insulator/PrOs$_{4}$Sb$_{12}$ Junctions

We theoretically investigate the tunnel conductance in normal-metal/insulator/superconductor and ferromagnet/insulator/superconductor junctions for the unconventional superconductor PrOs$_{4}$Sb$_{12}$. Using several pair potentials provided by group theoretical considerations, the conductance is calculated for singlet as well as triplet pairing. The result shows that the direction of the electric tunneling current and the relative orientation of the superconductor (i.e. position of point nodes) are two main factors that determine the shape of conductance spectrum for a junction. In addition, comparison with experimental results provide useful information regarding the actual symmetry of the pair potential in the superconducting phase of PrOs$_{4}$Sb$_{12}$.