Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor

Z. W. Anderson; Y. Tang; V. Nagarajan; M. K. Chan; C. J. Dorow; G. Yu; D. L. Abernathy; A. D. Christianson; L. Mangin-Thro; P. Steffens; T. Sterling; D. Reznik; D. Bounoua; Y. Sidis; P. Bourges; M. Greven

doi:10.1038/s41535-025-00804-0

Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor

Z. W. Anderson
, Y. Tang
, V. Nagarajan
, M. K. Chan
, C. J. Dorow
, G. Yu
, D. L. Abernathy
, A. D. Christianson
, L. Mangin-Thro
, P. Steffens
, T. Sterling
, D. Reznik
, D. Bounoua
, Y. Sidis
, P. Bourges
, M. Greven

Research output: Contribution to journal › Article › peer-review

Abstract

It is a distinct possibility that spin fluctuations are the pairing interactions in numerous unconventional superconductors. In the high-transition-temperature (high-T_c) 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 HgBa₂CuO_4+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 Δ_AF ≈ 6 meV, commensurate over a wide energy range, and disperses above about 55 meV. Given the pristine nature of HgBa₂CuO_4+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.

Original language	English
Article number	93
Journal	npj Quantum Materials
Volume	10
Issue number	1
DOIs	https://doi.org/10.1038/s41535-025-00804-0
State	Published - Dec 2025

Funding

The work at the University of Minnesota was funded by the U.S. Department of Energy through the University of Minnesota Center for Quantum Materials, under Grant No. DE-SC0016371. A portion of this research used resources at the Spallation Neutron Source, a Department of Energy Office of Science User Facility operated by Oak Ridge National Laboratory. Beam time was allocated to ARCS on proposals IPTS-8474 and IPTS-16717. Part of this research used resources at the Institute Laue-Langevin, via beam lines IN20 and D7. A portion of this research used resources at the Laboratoire Léon Brillouin, a facility funded by the French Atomic Energy Commission (CEA) and National Center for Scientific Research (CNRS), via beam line 2T. T.S. and D.R. acknowledge support by the U.S. Department of Energy, Office of Basic Energy Sciences, Office of Science, under Contract No. DE-SC0024117.

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Anderson, Z. W., Tang, Y., Nagarajan, V., Chan, M. K., Dorow, C. J., Yu, G., Abernathy, D. L., Christianson, A. D., Mangin-Thro, L., Steffens, P., Sterling, T., Reznik, D., Bounoua, D., Sidis, Y., Bourges, P., & Greven, M. (2025). Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor. npj Quantum Materials, 10(1), Article 93. https://doi.org/10.1038/s41535-025-00804-0

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title = "Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor",

abstract = "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.",

author = "Anderson, \{Z. W.\} and Y. Tang and V. Nagarajan and Chan, \{M. K.\} and Dorow, \{C. J.\} and G. Yu and Abernathy, \{D. L.\} and Christianson, \{A. D.\} and L. Mangin-Thro and P. Steffens and T. Sterling and D. Reznik and D. Bounoua and Y. Sidis and P. Bourges and M. Greven",

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Anderson, ZW, Tang, Y, Nagarajan, V, Chan, MK, Dorow, CJ, Yu, G, Abernathy, DL , Christianson, AD, Mangin-Thro, L, Steffens, P, Sterling, T, Reznik, D, Bounoua, D, Sidis, Y, Bourges, P & Greven, M 2025, 'Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor', npj Quantum Materials, vol. 10, no. 1, 93. https://doi.org/10.1038/s41535-025-00804-0

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T1 - Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor

AU - Anderson, Z. W.

AU - Tang, Y.

AU - Nagarajan, V.

AU - Chan, M. K.

AU - Dorow, C. J.

AU - Yu, G.

AU - Abernathy, D. L.

AU - Christianson, A. D.

AU - Mangin-Thro, L.

AU - Steffens, P.

AU - Sterling, T.

AU - Reznik, D.

AU - Bounoua, D.

AU - Sidis, Y.

AU - Bourges, P.

AU - Greven, M.

PY - 2025/12

Y1 - 2025/12

N2 - 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.

AB - 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.

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DO - 10.1038/s41535-025-00804-0

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VL - 10

JO - npj Quantum Materials

JF - npj Quantum Materials

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ER -

Gapped commensurate antiferromagnetic response in a strongly underdoped model cuprate superconductor

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