Superconductivity in PtPb$_{4}$ with Possible Nontrivial Band Topology

Abstract

Superconductivity in topological quantum materials is much sought after as it represents the key avenue to searching for topological superconductors, which host a full pairing gap in the bulk but Majorana bound states at the surface. To date, however, the simultaneous realization of nontrivial band topology and superconductivity in the same material under ambient conditions remains rare. In this paper, we study both superconducting and topological properties of a binary compound PtPb4 (Tc ∼ 2.7 K) that was recently reported to exhibit large Rashba splitting, inherent to the heavy 5d Pt and 6p Pb. We show that in PtPb4, the specific heat jump at Tc reaches ∆C/γTc∼1.70±0.04, larger than 1.43 expected for the weak-coupling BCS superconductors. Moreover, the measurement of quantum oscillation suggests the possibility for a topological band structure, which is further studied by density functional theory calculations. Our study may stimulate future experimental and theoretical investigations in this intriguing material.