Enhanced Superconductivity at Quantum-Critical KTaO3 Interfaces

Jieun Kim; Muqing Yu; Ahmed Omran; Jiangfeng Yang; Ranjani Ramachandran; William O. Nachlas; Patrick Irvin; Jeremy Levy; Chang-Beom Eom

arXiv · 2511.12904

Enhanced Superconductivity at Quantum-Critical KTaO3 Interfaces

Jieun Kim·Muqing Yu·Ahmed Omran·Jiangfeng Yang·Ranjani Ramachandran·William O. Nachlas·Patrick Irvin·Jeremy Levy·Chang-Beom Eom

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Abstract

Superconductivity at oxide interfaces has intrigued researchers for decades, yet the underlying pairing mechanism remains elusive. Here we demonstrate that proximity to a ferroelectric quantum critical point dramatically enhances interfacial superconductivity in KTaO3. By precisely tuning KTaO3 to its quantum critical composition through 0.8% niobium doping, we achieve a near-doubling of the superconducting transition temperature, reaching 2.9 K. Remarkably, a dome-shaped carrier density dependence emerges exclusively at the quantum critical point, contrasting sharply with the linear scaling observed in undoped interfaces. Our findings establish ferroelectric quantum criticality as a powerful mechanism for enhancing superconductivity and provide compelling evidence for soft-phonon-mediated pairing in these systems.

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Jieun Kim, Muqing Yu, Ahmed Omran, Jiangfeng Yang, Ranjani Ramachandran, William O. Nachlas, Patrick Irvin, Jeremy Levy, Chang-Beom Eom. 2025-11-17. Enhanced Superconductivity at Quantum-Critical KTaO3 Interfaces. https://arxiv.org/abs/2511.12904

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