Hallmark features of conventional BCS superconductivity in 2H-TaS2
Journal article, 2025
Layered transition metal dichalcogenides (TMDs) are model systems to investigate the interplay between superconductivity and the charge density wave (CDW) order. Here, we use muon spin rotation and relaxation (μ+SR) to probe the superconducting ground state of polycrystalline 2H-TaS2, which hosts a CDW transition at 76 K and superconductivity below 1 K. The μ+SR measurements, conducted down to 0.27 K, are consistent with a nodeless, BCS-like single-gap s-wave state. Fits to the temperature dependence of the depolarization rate and Knight shift measurements support spin-singlet pairing. Crucially, no evidence of time-reversal symmetry breaking (TRSB) is observed, distinguishing 2H-TaS2 from polymorphs like 4Hb-TaS2, where TRSB and unconventional superconductivity have been reported. These findings establish 2H-TaS2 as a canonical BCS superconductor and provide a reference point for understanding the diverse electronic ground states that emerge in structurally distinct TMD polymorphs.
Muon spin rotation μ+SR
Superconductivity
Van der Waals
Author
Frank Elson
Royal Institute of Technology (KTH)
Ola Kenji Forslund
University of Zürich
Uppsala University
Rasmus Palm
University of Tartu
Royal Institute of Technology (KTH)
Ahmed Alshemi
Lund University
Mahmoud Abdel-Hafiez
University of Sharjah
Gediminas Simutis
Paul Scherrer Institut
T. Shiroka
Paul Scherrer Institut
Swiss Federal Institute of Technology in Zürich (ETH)
D. Das
Paul Scherrer Institut
Elizabeth Blackburn
Lund University
Jonas Weissenrieder
Royal Institute of Technology (KTH)
Yasmine Sassa
Royal Institute of Technology (KTH)
Chalmers, Physics, Materials Physics
Martin Månsson
Royal Institute of Technology (KTH)
Scientific Reports
2045-2322 (ISSN) 20452322 (eISSN)
Vol. 15 1 37164Subject Categories (SSIF 2025)
Condensed Matter Physics
DOI
10.1038/s41598-025-24342-8