Point-contact enhanced superconductivity in trigonal PtBi2: quest for the origin of ‘high-Tc

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • O. E. Kvitnitskaya - , NASU - B. Verkin Institute for Low Temperature Physics and Engineering, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • L. Harnagea - , Leibniz Institute for Solid State and Materials Research Dresden, Indian Institute of Science Education and Research Pune (Author)
  • G. Shipunov - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • S. Aswartham - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • I. Kovalchuk - , Kyiv Academic University (Author)
  • V. V. Fisun - , NASU - B. Verkin Institute for Low Temperature Physics and Engineering (Author)
  • D. V. Efremov - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • B. Büchner - , Clusters of Excellence ctd.qmat: Complexity, Topology and Dynamics in Quantum Matter, Chair of Experimental Solid State Physics, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Yu G. Naidyuk - , NASU - B. Verkin Institute for Low Temperature Physics and Engineering (Author)

Abstract

We studied enhanced superconductivity in point contacts (PCs) based on a type-I Weyl semimetal trigonal t-PtBi2 using both normal metal (Ag, Cu, Pt) and ferromagnetic (Fe, Co, Ni) tips by measuring the differential resistance dV/dI(V) curves. In most cases, the value of the superconducting critical temperature (Tc) ranges between 3 and 5 K, which is several times higher than the maximum bulk Tc. Notably, among the various PCs we examined, a few achieved Tc values as high as 8 K, including those with both normal and ferromagnetic tips. Additionally, the critical magnetic field is also highly enhanced in these PCs and reaches up to several Tesla. The common reason for the Tc increase may be related to pressure/strain caused during the PC’s formation. It is worth noting that a greater increase in Tc is observed in PCs formed at the edge of the sample flake, compared to those formed on the plane of the platelet. The results also reveal that the enhancement of Tc in PCs based on t-PtBi2 is compatible with ferromagnetic tips, which may suggest a potentially complex nature of enhanced superconductivity. Our findings suggest that t-PtBi2 is a promising candidate for realizing topological superconductivity at more accessible temperatures.

Details

Original languageEnglish
Article number055004
JournalSuperconductor science and technology
Volume39
Issue number5
Publication statusPublished - 1 May 2026
Peer-reviewedYes

Keywords

Keywords

  • enhanced superconductivity, t-PtBi, type-I Weyl semimetal, point contacts