g-Factor-Enhanced Upper Critical Field in Superconducting PdTe2 due to Quantum Confinement
Abstract The Pauli limiting field imposed by the Zeeman effect bounds the upper critical field of weak-coupling superconductivity. It is determined by setting the condensation energy equal to the paramagnetic energy and scales inversely with the effective g-factor. Here, we demonstrate that in a few-layer-thick van der Waals superconductor, PdTe2, quantum confinement can tune the effective g-factor causing the Pauli limit to become thickness-dependent. We experimentally probe the in-plane upper critical field, Hc2∥, of PdTe2 at multiple intermediate thicknesses down to 20 mK. We find that Hc2∥ is enhanced by more than an order of magnitude as the thickness is reduced from 50 nm down to 17 nm. We model the temperature- and thickness-dependent Hc2||, revealing a thickness-dependent spin Zeeman depairing mechanism impacting its value. Our findings reveal how quantum confinement drives a reduction in g that enhances the Pauli limiting field and allows the measured enhancement of Hc2∥. A violation of the Pauli limit is often associated with unconventional pairing symmetry in superconductors. Our work demonstrates that this simple association is difficult without knowledge of the g-factor, particularly in layered materials.
Authors
- Badih A. Assaf (ORCID: https://orcid.org/0000-0002-6879-9651)
- Daichi Kozawa (ORCID: https://orcid.org/0000-0002-0629-5589)
- Shan Feng Zou (ORCID: https://orcid.org/0000-0002-7642-1624)
- David Graf (ORCID: https://orcid.org/0000-0002-0504-8527)
- Tzu-Chi Hsieh (ORCID: https://orcid.org/0000-0002-6109-3357)
- Dmitry V. Chichinadze (ORCID: https://orcid.org/0000-0001-8713-4500)
- Dafei Jin (ORCID: https://orcid.org/0000-0002-8035-3580)
- R. Nowell
- Ryo Kitaura (ORCID: https://orcid.org/0000-0001-8108-109X)
- Huiyang Ma
- Kota Yoshimura
- Yi‐Ting Hsu (ORCID: https://orcid.org/0000-0002-6340-8404)
- Xinyu Liu (ORCID: https://orcid.org/0000-0002-7004-6878)
- Xiaolong Liu (ORCID: https://orcid.org/0000-0002-6186-5257)
- Muhsin Abdul Karim
- Michael Stuckert
- Bence G. Márkus (ORCID: https://orcid.org/0000-0003-1472-0482)
- László Forró
- Cyprian Lewandowski
Institutions
- Florida State University (US)
- University of Notre Dame (US)
- University of Tsukuba (JP)
- National Institute for Materials Science (JP)
- National High Magnetic Field Laboratory (US)
Publication Details
- Journal
- ACS Nano
- Published
- 2026-08-20
- DOI
- https://doi.org/10.1021/acsnano.6c07055
- Primary Topic
- Topological Materials and Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- U.S. Department of Energy
- Florida State University
- National High Magnetic Field Laboratory
- Ministry of Education, Culture, Sports, Science and Technology
- Japan Society for the Promotion of Science
- National Institute for Materials Science
- Division of Materials Research
- Basic Energy Sciences
- High Magnetic Field Laboratory, Chinese Academy of Sciences