Probing the superconducting gap symmetry of 3D Dirac semimetal PdTe

The search for new materials with superconducting ground states featuring topological characteristics is crucial for realizing Majorana bound states. PdTe is a noteworthy candidate, exhibiting superconductivity below 4.5 K and possessing a topologically non-trivial band structure. ARPES studies classify PdTe as a 3D Dirac semimetal, with a Dirac point situated close to the Fermi level, making it particularly intriguing for investigating the nature of superconductivity. Further ARPES findings suggest the coexistence of surface-nodeless and bulk-nodal gap structures, attributed to spin-orbit coupling. Complementary specific heat studies down to 50 mK indicate the presence of nodal bulk gaps. However, the absence of a linear term in thermal conductivity and the upward curvature observed in the H-T phase diagram suggest a multiband nature of superconductivity with nodeless gaps. To elucidate which of these scenarios is realized in PdTe, a detailed microscopic investigation is necessary. Therefore, we propose conducting an in-depth μSR study in both transverse field and zero field configurations to determine the precise nature of the superconducting gap symmetry and to assess the presence or absence of any minute magnetic fields resulting from spin-orbit coupling.