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Hallmark features of conventional BCS superconductivity in 2H-TaS2

Elson, Frank ; Kenji Forslund, Ola ; Palm, Rasmus ; Alshemi, Ahmed LU orcid ; Abdel-Hafiez, Mahmoud ; Simutis, Gediminas ; Shiroka, Toni ; Das, Debarchan ; Blackburn, Elizabeth LU and Weissenrieder, Jonas LU , et al. (2025) In Scientific Reports 15(1).
Abstract

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... (More)

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.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Muon spin rotation μSR, Superconductivity, Van der Waals
in
Scientific Reports
volume
15
issue
1
article number
37164
publisher
Nature Publishing Group
external identifiers
  • scopus:105019493598
  • pmid:41131324
ISSN
2045-2322
DOI
10.1038/s41598-025-24342-8
language
English
LU publication?
yes
id
5df994a7-4755-4c29-94a1-62775dcbb00b
date added to LUP
2025-12-10 14:40:03
date last changed
2025-12-11 03:37:02
@article{5df994a7-4755-4c29-94a1-62775dcbb00b,
  abstract     = {{<p>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<sup>+</sup>SR) to probe the superconducting ground state of polycrystalline 2H-TaS<sub>2</sub>, which hosts a CDW transition at 76 K and superconductivity below 1 K. The μ<sup>+</sup>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-TaS<sub>2</sub> from polymorphs like 4Hb-TaS<sub>2</sub>, where TRSB and unconventional superconductivity have been reported. These findings establish 2H-TaS<sub>2</sub> as a canonical BCS superconductor and provide a reference point for understanding the diverse electronic ground states that emerge in structurally distinct TMD polymorphs.</p>}},
  author       = {{Elson, Frank and Kenji Forslund, Ola and Palm, Rasmus and Alshemi, Ahmed and Abdel-Hafiez, Mahmoud and Simutis, Gediminas and Shiroka, Toni and Das, Debarchan and Blackburn, Elizabeth and Weissenrieder, Jonas and Sassa, Yasmine and Månsson, Martin}},
  issn         = {{2045-2322}},
  keywords     = {{Muon spin rotation μSR; Superconductivity; Van der Waals}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Hallmark features of conventional BCS superconductivity in 2H-TaS<sub>2</sub>}},
  url          = {{http://dx.doi.org/10.1038/s41598-025-24342-8}},
  doi          = {{10.1038/s41598-025-24342-8}},
  volume       = {{15}},
  year         = {{2025}},
}