Work

Machine-learning test of the single-ion model for d d excitations in cuprates

Year: 2026

Type: article

Abstract: We investigate $dd$ excitations in Resonant Inelastic X-ray Scattering spectra of YBa$_2$Cu$_3$O$_6$ and La$_2$CuO$_4$ using the local single-ion model. The data are analyzed by conventional global fitting and by a convolutional neural network trained within the same theoretical framework. For YBa$_2$Cu$_3$O$_6$, the excited state energies obtained with the two methods coincide, leading to the $xy$, $3z^2-r^2$, $xz/yz$ sequence for increasing energy. This result validates the use of machine learning tools for the analysis of RIXS spectra dominated by $dd$ excitations. By contrast, for La$_2$CuO$_4$, the two methods do not converge to a single solution, revealing the limitations of the single-ion model in describing $dd$ excitations in cuprates and pointing to the role of additional contributions beyond a purely local picture in shaping high-energy excitations.

Source: Physical review. B./Physical review. B

DOI: 10.1103/tn4y-t5ml

Authors: Maryia Zinouyeva, Leonardo Martinelli, Riccardo Arpaia, Nicholas B. Brookes, Daniele Di Castro, Kurt Kummer, Floriana Lombardi, Giacomo Merzoni, Francesco Rosa, Alessandro Tarasio, Enrico Tassi, Flora Yakhou-Harris, Ezio Puppin, Marco Moretti Sala, Giacomo Ghiringhelli

Language: English

Topic: Physics of Superconductivity and Magnetism

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: European Synchrotron Radiation Facility, Knut och Alice Wallenbergs Stiftelse, Vetenskapsrådet

Award: Revealing strongly entangled quantum matter in High-Tc superconductor devices

OpenAlex ID: W7169764312

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