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 ultrahigh 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, 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.
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https://hal.archives-ouvertes.fr/hal-02351848
Contributor : Shamashis Sengupta <>
Submitted on : Wednesday, November 6, 2019 - 3:34:55 PM
Last modification on : Friday, November 8, 2019 - 1:20:51 AM

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Shamashis Sengupta, Emilie Tisserond, Florence Linez, Miguel Monteverde, Anil Murani, et al.. Gate-tunable superconductivity at SrTiO3 surface realized by Al layer evaporation. Journal of Applied Physics, American Institute of Physics, 2018, 124 (21), pp.213902. ⟨10.1063/1.5049363⟩. ⟨hal-02351848⟩

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