Gate-tunable superconductivity at SrTiO3 surface realized by Al layer evaporation

Abstract

Electronic properties of low dimensional superconductors are determined by many-body-effects. This physics has been studied traditionally with superconducting thin films, and in recent times with two-dimensional electron gases (2DEGs) at oxide interfaces. In this work, we show that a superconducting 2DEG can be generated by simply evaporating a thin layer of metallic Al under ultra-high vacuum on a SrTiO3 crystal, whereby Al oxidizes into amorphous insulating alumina, doping the SrTiO3 surface with oxygen vacancies. The superconducting critical temperature of the resulting 2DEG is found to be tunable with a gate voltage with a maximum value of 360 mK. A gate-induced switching between superconducting and resistive states is demonstrated. Compared to conventionally-used pulsed-laser deposition (PLD), our work simplifies to a large extent the process of fabricating oxide-based superconducting 2DEGs. It will make such systems accessible to a broad range of experimental techniques useful to understand low-dimensional phase transitions and complex many-body-phenomena in electronic systems.

arXiv comment15 pages, 5 figures

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Cited by in corpus (5)

• Anisotropic Electronic Structure of the Two-Dimensional Electron Gas at the AlOx/KTaO3(110) interface
• Controlling the electronic interface properties of AlO${}_x$/SrTiO${}_3$ heterostructures
• Quantum interference effects of out-of-plane confinement on two-dimensional electron systems in oxides
• High stability 2D electron gases formed in Si3N4/Al//KTaO3 heterostructures: synthesis and in-depth interfacial characterization
• Density-tuned isotherms and dynamic change at phase transition in a gate-controlled superconducting system