Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor
It is a distinct possibility that spin fluctuations are the pairing interactions in numerous unconventional superconductors. In the high-transition-temperature (high-Tc) cuprates, superconductivity emerges upon doping antiferromagnetic Mott insulators, and spin fluctuations might furthermore drive unusual pseudogap phenomena. Here we use magnetic neutron scattering to study the highly underdoped cuprate HgBa2CuO4+δ (hole concentration p ≈ 0.064). In contrast to prior results for other underdoped cuprates, we find no evidence of incommensurate magnetic order associated with spin-density-wave or stripe correlations. Instead, the antiferromagnetic response in both the superconducting and pseudogap states is gapped below ΔAF ≈ 6 meV, commensurate over a wide energy range, and disperses above about 55 meV. Given the pristine nature of HgBa2CuO4+δ, which exhibits high structural symmetry and minimal point disorder effects, this behavior likely signifies the unmasked response of the underlying CuO2 planes near the Mott-insulating state. These results serve as a benchmark for a refined theoretical understanding of the cuprates.
Authors
- Dalila Bounoua (ORCID: https://orcid.org/0000-0003-0860-1321)
- Zach Anderson (ORCID: https://orcid.org/0000-0002-4221-2592)
- M. Greven (ORCID: https://orcid.org/0000-0002-8055-4358)
- T. Sterling
- A. D. Christianson (ORCID: https://orcid.org/0000-0003-3369-5884)
- Vikram Nagarajan (ORCID: https://orcid.org/0000-0003-1589-1283)
- Lucile Mangin-Thro (ORCID: https://orcid.org/0000-0001-9026-4410)
- Y. Sidis (ORCID: https://orcid.org/0000-0002-9333-0169)
- M. K. Chan (ORCID: https://orcid.org/0000-0002-8808-9040)
- D. Reznik
- P. Steffens (ORCID: https://orcid.org/0000-0002-7034-4031)
- P. Bourges (ORCID: https://orcid.org/0000-0001-9494-0789)
- D. L. Abernathy (ORCID: https://orcid.org/0000-0002-3533-003X)
- Yang Tang (ORCID: https://orcid.org/0000-0002-3158-7487)
- C. J. Dorow (ORCID: https://orcid.org/0000-0002-7593-4057)
- Guichuan Yu (ORCID: https://orcid.org/0000-0002-7533-6911)
Institutions
- Oak Ridge National Laboratory (US)
- Centre National de la Recherche Scientifique (FR)
- University of Minnesota (US)
- University of Colorado Boulder (US)
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR)
- Université Paris-Saclay (FR)
- University of Minnesota System (US)
- Institut Laue-Langevin (FR)
- Laboratoire Léon Brillouin (FR)
- CEA Paris-Saclay (FR)
Publication Details
- Journal
- npj Quantum Materials
- Published
- 2025-08-20
- DOI
- https://doi.org/10.1038/s41535-025-00804-0
- Primary Topic
- Physics of Superconductivity and Magnetism
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- U.S. Department of Energy
- University of Minnesota
- Centre National de la Recherche Scientifique
- Office of Science
- Basic Energy Sciences
- Oak Ridge National Laboratory