Dominant $s$-wave superconducting gap in PdTe$_2$ observed by tunneling spectroscopy on side-junctions

Abstract

We have fabricated superconductor-normal metal side-junctions with different barrier transparencies out of PdTe$_2$ crystalline flakes and measured the differential conductance spectra. Modeling our measurements using a modified Blonder Tinkham 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 PdTe$_2$ is dominated by conventional $s$-wave pairing.