Evidence of unconventional superconductivity in Dirac semimetal PdTe via point contact spectroscopy

Palladium telluride (PdTe), a non-layered intermetallic crystalline Dirac semimetal, captured attention for its unique superconducting properties. In this work, we investigate the superconducting state of PdTe using point-contact Andreev reflection spectroscopy (PCAR) that offers direct insight into the superconducting gap magnitude and superconducting gap symmetry. Measurements were performed down to 2K with and without magnetic field. The experimental data are analyzed using the Blonder-Tinkham-Klapwijk formalism considering<i>s-</i>wave<i>,</i>multiband<i>s</i>+<i>s</i>wave<i>, p-</i>wave and<i>d -</i>wave symmetries. Conventional<i>s</i>-wave and multi-gap<i>s+s</i>wave models fail to reproduce the essential spectral features, even when incorporating variations in interface transparency and quasiparticle broadening. In contrast, the experimental data show excellent agreement with anisotropic<i>p</i>-wave and<i>d</i>-wave models, exhibiting characteristics consistent with nodal anisotropic gap structures. The observed anisotropic gap structure and pronounced deviations from conventional BCS behavior highlight the complex nature of the pairing interactions in PdTe. These findings provide strong evidence of unconventional pairing symmetry in this material.