Dominant s-wave superconducting gap in PdTe₂ observed by tunneling spectroscopy on side junctions

We have fabricated superconductor-normal metal side junctions with different barrier transparencies out of PdTe₂ crystalline flakes and measured the differential conductance spectra. Modeling our measurements using a modified Blonder, Tinkham, and Klapwijk (BTK) formalism confirms that the superconductivity is mostly comprised of the conventional s-wave symmetry. We have found that for junctions with very low barrier transparencies, the junctions can enter a thermal regime, where the critical current becomes important. Adding this to the BTK model allows us to accurately fit the experimental data, from which we conclude that the superconductivity in the a-b plane of PdTe2 is dominated by conventional s-wave pairing.