Year: 2026
Type: preprint
Abstract: Understanding how magnetic excitations and exchange interactions evolve with doping is crucial for deciphering the physics that shapes the phase diagram of high-temperature cuprate superconductors. Here, we clearly determine the behavior of the paramagnon dispersion in the oxychloride cuprate Na$_{x}$Ca$_{2-x}$CuO$_2$Cl$_2$ up to the highest doping level. We find that the paramagnon bandwidth, defined by the energy at the $X$ zone boundary $(0.5,0,0)$, remains unchanged within experimental uncertainty, even though it exhibits significant broadening. In contrast, along the nodal direction $Γ-M$ (\textit{i.e.}, from $(0,0,0)$ to $(0.5,0.5,0)$), the paramagnon energy shows a marked softening with doping, with a shift of up to $ΔE\sim150$ meV at the midpoint of the zone for the highest doping, which is about half of its initial value in the antiferromagnetic phase. Calculations of the dynamical spin structure factor for a one-band Hubbard model, including hopping terms up to the third-nearest neighbor ($t^{\prime\prime}$), explain this behavior and accurately reproduce the observed wave vector dependence and directional variation in the Brillouin zone.
Source: arXiv (Cornell University)
Authors: Fawaz, Chafic, Gaspard, Léo, Chaix, Laura, Laveder, Luca, Bacq-Labreuil, Benjamin, Porée, Victor, Yakhou-Harris, Flora, Kummer, Kurt, Brookes, Nicholas B., Nicolaou, Alessandro, Yamamoto, Hajime, Okazaki, Yuichi, Yamada, Ikuya, Azuma, Masaki, Santos-Cottin, David, Méasson, Marie-Aude, Lenz, Benjamin, d'Astuto, Matteo
Institutions: Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Institut Néel, Sorbonne Université, Institut de minéralogie, de physique des matériaux et de cosmochimie, Structure et Instabilité des Génomes, Université de Sherbrooke, Regroupement Québécois sur les Matériaux de Pointe, Institut de Physique et Chimie des Matériaux de Strasbourg, Institut quantique, Université de Strasbourg, Synchrotron SOLEIL, European Synchrotron Radiation Facility, Tokyo Institute of Technology, Institut des Sciences Chimiques de Rennes, Université de Rennes, Osaka Prefecture University, Institute of Integrated Research, Institute of Science Tokyo, Materials & Structures Laboratory, University of Fribourg
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220723600