Multigap nodeless superconductivity in the topological semimetal PdTe

Recently PdTe was identified as a spin-orbit coupled topological Dirac semimetal and was claimed\nto exhibit both bulk-nodal and surface-nodeless superconducting gaps. Here we report the ultralowtemperature\nthermal conductivity measurements on PdTe single crystals with Tc = 4.5 K to\ninvestigate its superconducting gap structure. It is found that the residual linear term κ0/T is\nnegligible in zero magnetic field. Furthermore, the field dependence of κ0(H)/T exhibits an Sshaped\ncurve. These results suggest that PdTe has multiple nodeless superconducting gaps, which is\nat odds with the claimed bulk-nodal gap. The reason for the discrepancy is likely that previous angleresolved\nphotoemission spectroscopy measurements were only performed down to 2 K and cannot\nobserve the smaller nodeless gap. The fully gapped superconducting state in PdTe is compatible\nwith it being a topological superconductor candidate.