Oral: Signature of point nodal superconductivity in the Dirac semimetal PdTe

Recent discoveries of materials that show both topological semimetal behavior and superconductivity have advanced the research, providing new ways to explore the interaction between topology and superconductivity. PdTe is a 3D Dirac semimetal, exhibiting type- II superconducting behavior with a transition temperature (T_c) ∼ 4.5 K. Recent ARPES experiments have revealed the coexistence of bulk-nodal and surface-nodeless cooper pairings in PdTe. However, the thermal-conductivity measurements on PdTe single crystals suggest that PdTe has multiple nodeless superconducting gaps, which contradicts the bulk-nodal gap claim. We carried out thermodynamic transport experiments on PdTe single crystals. Our field-dependent specific heat data down to temperatures ∼ 58 mK shows a power-law field dependence, which differs from the usual linear behavior expected for an isotropic fully gapped s-wave superconductor. Additionally, our zero-field specific heat data reveals a clear ∼ T³ temperature dependence at low temperatures (T < T_c/3), suggesting the presence of bulk point nodes in the superconducting order parameter of PdTe. A weak-coupling BCS-type order parameter with p-wave symmetry and point nodes fits the zero-field data well. These bulk measurements indicate PdTe to be an odd-parity p-wave superconductor.