Unveiling the nature of collective charge excitations in a cuprate superconductor

Xunyang Hong; Yujie Yan; Leonardo Martinelli; Izabela Biało; Karin von Arx; Jaewon Choi; Yasmine Sassa; Sunseng Pyon; Tomohiro Takayama; Hidenori Takagi; Chafic Fawaz; Laura Chaix; Mehdi Frachet; Igor Vinograd; Flora Yakhou; Kaya Vogler; Dan Zhao; Yanbing Zhou; Tao Wu; Xianhui Chen; Marc-Henri Julien; Mirian Garcia-Fernandez; Ke-Jin Zhou; Johan Chang; Qisi Wang

doi:10.59717/j.tip.2026.100011

The Innovation Physics > 2026 Vol. 1 > No. 1 > 100011

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Unveiling the nature of collective charge excitations in a cuprate superconductor

1.
Department of Physics, The Chinese University of Hong Kong, Hong Kong SAR 999077, China
2.
Physik-Institut, Universität Zürich, Winterthurerstrasse 190, Zürich CH-8057, Switzerland
3.
Diamond Light Source, Harwell Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
4.
Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Daejeon 34141, South Korea
5.
Department of Applied Physics, KTH Royal Institute of Technology, Stockholm SE-106 91, Sweden
6.
Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
7.
Max Planck Institute for Solid State Research, Stuttgart 70569, Germany
8.
Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
9.
Institut Néel, CNRS and Université Grenoble Alpes, Grenoble 38042, France
10.
Univ. Grenoble Alpes, CNRS, Univ. Toulouse, INSA-T, LNCMI-EMFL, Grenoble UPR3228, France
11.
European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043, France
12.
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
13.
CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, Department of Physics, University of Science and Technology of China, Hefei 230026, China
14.
Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
15.
State Key Laboratory of Quantum Information Technologies and Materials, The Chinese University of Hong Kong, Hong Kong SAR 999077, China

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Corresponding authors: johan.chang@physik.uzh.ch (J.C.); qwang@cuhk.edu.hk (Q.W.)
Received Date: April 29, 2026

Accepted Date: September 09, 2026

Published Online: September 16, 2026

The Innovation Physics 1(1), https://doi.org/10.59717/j.tip.2026.100011 | Cite this article

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1. Dispersive charge excitations are observed in a stripe-ordered cuprate.
  
  Their velocity is comparable to that of spin excitations, linking charge and spin dynamics.
  
  Phonon modeling separates weak charge signals from overlapping lattice vibrations.

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ABSTRACT

Emergent symmetry breakings in condensed matter systems are often intimately linked to collective excitations. For example, the intertwined spin-charge stripe order in cuprate superconductors is associated with spin and charge excitations. While the collective behavior of spin excitations is well established, the nature of charge excitations remains to be understood. Here we present a high-resolution resonant inelastic x-ray scattering (RIXS) study of charge excitations in the stripe-ordered cuprate La_1.675Eu_0.2Sr_0.125CuO₄. The RIXS spectra consist of both charge and phonon excitations around the charge ordering wave vector. By modeling the momentum-dependent phonon intensity, the charge-excitation spectral weight is extracted over a wide energy range. As such, we reveal the highly dispersive nature of the charge excitations, with an energy scale comparable to the spin excitations. Since charge order and superconductivity in cuprates are possibly driven by the same electronic correlations, determining the interaction strength underlying charge order is essential to establishing a comprehensive microscopic model of high-temperature superconductivity.
- Charge excitations /
- Superconductivity /
- Cuprates

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Cite this article:

Hong X., Yan Y., Martinelli L., et al. (2026). Unveiling the nature of collective charge excitations in a cuprate superconductor. The Innovation Physics 1:100011. https://doi.org/10.59717/j.tip.2026.100011

Hong X., Yan Y., Martinelli L., et al. (2026). Unveiling the nature of collective charge excitations in a cuprate superconductor. The Innovation Physics 1:100011. https://doi.org/10.59717/j.tip.2026.100011

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Unveiling the nature of collective charge excitations in a cuprate superconductor

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