Evidence for orbital Fulde-Ferrell-Larkin-Ovchinnikov state in the bulk limit of 2H-NbSe2
The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is an unusual superconducting phase that survives beyond the Pauli paramagnetic limit through spatial modulation of the order parameter. An even more exotic variant-the orbital FFLO state-was recently reported in thin flakes of 2H-NbSe<sub>2</sub>, involving the interplay of Ising spin-orbit coupling and orbital pair breaking. Here, we report thermodynamic signatures consistent with an orbital FFLO state in bulk 2H-NbSe<sub>2</sub>, based on high-resolution magnetization and torque measurements under strictly parallel to the NbSe<sub>2</sub> basal plane. In the magnetic phase diagram, a crossover to a first-order transition appears above 3 T and disappears with slight field misalignment, indicating field-angle dependent Pauli-limited behavior. Additionally, we observe a reversible step-like anomaly within the superconducting state, and a pronounced six-fold in-plane modulation of the upper critical field above this phase transition. These results suggest that the orbital FFLO state is likely realized even in the bulk limit of 2H-NbSe<sub>2</sub>.
Authors
- Rolf Lortz (ORCID: https://orcid.org/0000-0002-4075-9375)
- Noah F. Q. Yuan (ORCID: https://orcid.org/0000-0001-7546-8095)
- Cheuk Yin Ng
- Jaemun Park (ORCID: https://orcid.org/0000-0002-2818-3561)
- Chang-Woo Cho
- Beopgil Cho (ORCID: https://orcid.org/0000-0003-2023-6363)
- Mahmoud Abdel-Hafiez (ORCID: https://orcid.org/0000-0002-1802-5279)
- Kwan To Lo
- Keeseong Park (ORCID: https://orcid.org/0000-0002-2539-0135)
- Abdel Rahman Allan
- Timothée Tianyu Lortz
- Shek Hei Chui
Institutions
- Uppsala University (SE)
- Centre National de la Recherche Scientifique (FR)
- Université Toulouse III - Paul Sabatier (FR)
- Université Fédérale de Toulouse Midi-Pyrénées (FR)
- Shanghai Jiao Tong University (CN)
- Daegu Gyeongbuk Institute of Science and Technology (KR)
- Chungnam National University (KR)
- Institut National des Sciences Appliquées de Toulouse (FR)
- Hong Kong University of Science and Technology (HK)
- University of Sharjah (AE)
- University of Hong Kong (HK)
- Université Grenoble Alpes (FR)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-08-15
- DOI
- https://doi.org/10.1038/s41467-025-62223-w
- Citations
- 1
- Primary Topic
- Organic and Molecular Conductors Research
- Type
- article
- Field-Weighted Citation Impact
- 0.43
Funders
- Research Grants Council, University Grants Committee
- Daegu Gyeongbuk Institute of Science and Technology