Unveiling the electronic structure of the predicted topological superconductor PbTaS2

PbTaS₂ is a metal intercalated, layered transition metal dichalcogenide compound which has recently been predicted to be a potential topological superconductor (TSC), with a superconducting transition temperature of 2. 6 K. Besides the strong interest in this class of materials, because of their high potential in quantum-computing applications, many aspects of their phenomenology are still undisclosed. Combining angle-resolved photoemission spectroscopy measurements and density functional theory calculations, we have studied the electronic properties of the centrosymmetric type-II superconductor PbTaS₂ single crystals in the metallic phase, showing the presence of surface states, originated from the Pb-terminated surface, and of topological nodal lines, formed by the crossing of Ta dₗₘ/dₗ^{2-y^2} and Pb pₗ/pₘ orbitals. The evidence of surface states connecting the nodal lines, as already discovered on structurally similar materials to be typical features of nodal-line semimetal-like TSCs, makes PbTaS₂ a good candidate for exploring topological superconductivity.