Superconductivity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>PtPb</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:math> with possible nontrivial band topology
Chunqiang Xu, Bin Li, Linpeng Zhang, J. Pollanen, X. L. Yi, Xiangzhuo Xing, Yi Liu, Jinhua Wang, Zengwei Zhu, Zhixiang Shi, Xiaofeng Xu, Xianglin Ke
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 the binary compound ${\mathrm{PtPb}}_{4}$ $({T}_{c}\ensuremath{\sim}2.7 \mathrm{K})$ that was recently reported to exhibit large Rashba splitting, inherent to the heavy $5d$ Pt and $6p$ Pb. We show that in ${\mathrm{PtPb}}_{4}$, the specific heat jump at ${T}_{c}$ reaches $\mathrm{\ensuremath{\Delta}}C/\ensuremath{\gamma}{T}_{c}\ensuremath{\sim}1.70\ifmmode\pm\else\textpm\fi{}0.04$, larger than the 1.43 expected for weak-coupling BCS superconductors. Moreover, the measurement of quantum oscillation suggests the possibility of 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.