Researchers reveal how inversion symmetry breaking and tunable localized polar phonons correlate with superconductivity, providing evidence that lattice dynamics and strong electron–phonon coupling may contribute to pairing near ferroelectric quantum criticality in quantum paraelectric systems and materials.
Application sectors: Quantum materials and superconducting-materials research, Superconducting electronics, Oxide-interface and quantum-device engineering.
Keywords: Superconductivity; oxide interfaces; electron–phonon coupling; localized phonons; ferroelectric quantum criticality.
The microscopic origin of superconductivity at oxide interfaces remains an open question, particularly regarding the role of lattice dynamics near ferroelectric quantum criticality. In this study, R. Guzman and collaborators investigate LaAlO₃/SrTiO₃ interfaces across the superconducting phase diagram using momentum-selective vibrational spectroscopy in a scanning transmission electron microscope, together with atomic-structure analysis.
Published in Nature Materials, the work identifies a correlation between superconductivity, inversion symmetry breaking and the emergence of high-frequency localized phonons. These polar vibrations are confined near the interface, evolve systematically with carrier density and exhibit strong electron–phonon coupling. The findings establish a direct connection between lattice instability, tunable localized phonons and superconductivity, providing evidence for a possible phonon-mediated contribution to pairing in quantum paraelectric systems.
The results offer microscopic guidance for understanding and engineering superconducting oxide interfaces and other tunable quantum materials.
Reference paper
R. Guzman, M. Xu, M. Pruneda, J. P. Nery, A. Li, N. Wittemeier, A. Li, G. Singh, G. Herranz, N. Bergeal, A. Kalaboukhov, J. Gazquez, and W. Zhou, “Electron–phonon coupling and symmetry breaking in superconducting oxide interfaces near ferroelectric quantum criticality,” Nature Materials (2026). DOI: 10.1038/s41563-026-02647-x.