Lifshitz-enhanced superfluid density in two-gap superconducting TiSe2
Journal article, 2026
Superconductivity in TiSe2 emerges when the charge density wave (CDW) order is suppressed under pressure or doping. Recent theoretical and experimental studies suggest that a Lifshitz transition plays a key role in stabilizing the superconducting phase. Here, we present muon spin resonance measurements of pressurized TiSe2 , revealing a two-gap superconducting state. Our results indicate that the smaller gap contributes unexpectedly strongly to the total superfluid density. This effect is consistent with an enhanced density of states in a newly formed Fermi surface pocket at the Lifshitz transition. These findings provide microscopic insight into the interplay between CDW suppression, Fermi surface reconstruction, and multi-gap superconductivity in TiSe2 , demonstrating how pressure-induced changes in electronic structure can shape superconducting properties in layered materials.
Author
Frank Elson
Royal Institute of Technology (KTH)
J. Philippe
University of Zürich
Paul Scherrer Institut
Gediminas Simutis
Paul Scherrer Institut
Ola Kenji Forslund
Uppsala University
University of Zürich
Chalmers, Physics, Materials Physics
Mahmoud Abdel-Hafiez
University of Sharjah
Marc Janoschek
University of Zürich
Paul Scherrer Institut
Rustem Khasanov
Paul Scherrer Institut
D. Das
Paul Scherrer Institut
Jonas Weissenrieder
Royal Institute of Technology (KTH)
D. W. Tam
Royal Institute of Technology (KTH)
Yasmine Sassa
Royal Institute of Technology (KTH)
Martin Månsson
Royal Institute of Technology (KTH)
npj Quantum Materials
23974648 (eISSN)
Vol. 11 1 4Subject Categories (SSIF 2025)
Condensed Matter Physics
DOI
10.1038/s41535-025-00834-8