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arXiv · 2506.17056

Electric field control of superconducting fluctuations and quasiparticle interference at oxide interfaces

Graham Kimbell·Ulderico Filippozzi·Stefano Gariglio·Marc Gabay·Andreas Glatz·Andrey Varlamov·Andrea Caviglia
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Abstract

We investigate tunable superconducting transitions in (111)$\mathrm{LaAlO}_3/\mathrm{KTaO}_3$ field-effect devices. Large increases in conductivity, associated with superconducting fluctuations, are observed far above the transition temperature. However, the standard Aslamazov-Larkin paraconductivity model significantly underestimates the effect observed here. We use a model that includes conductivity corrections from normal state quasiparticle interference together with all contributions from superconducting fluctuations evaluated at arbitrary temperatures and in the short-wavelength limit. Through analysis of the magnetoconductance and resistive transitions, we find that the large conductivity increase can be explained by a combination of weak anti-localization and Maki-Thompson superconducting fluctuations. Both contributions are enabled by a strong temperature dependence of the electron's decoherence time compatible with an electron-phonon scattering scenario. We find that conductivity corrections are modulated by the electrostatic field effect, that governs a competition between normal-state quasiparticle interference and superconducting fluctuations.

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Graham Kimbell, Ulderico Filippozzi, Stefano Gariglio, Marc Gabay, Andreas Glatz, Andrey Varlamov, Andrea Caviglia. 2025-06-20. Electric field control of superconducting fluctuations and quasiparticle interference at oxide interfaces. https://arxiv.org/abs/2506.17056

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