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Freestanding oxide membranes constitute an intriguing material platform for new functionalities and allow integration of oxide electronics with technologically important platforms such as silicon. Sambri et al. recently reported a method to fabricate freestanding LaAlO3/SrTiO3 (LAO/STO) membranes by spalling of strained heterostructures. Here, we first develop a scheme for the high-yield fabrication of membrane devices on silicon. Second, we show that the membranes exhibit metallic conductivity and a superconducting phase below ∼200 mK. Using anisotropic magnetotransport we extract the superconducting phase coherence length ξ ≈ 36–80 nm and establish an upper bound on the thickness of the superconducting electron gas d ≈ 17–33 nm, thus confirming its two-dimensional character. Finally, we show that the critical current can be modulated using a silicon-based backgate. The ability to form superconducting nanostructures of LAO/STO membranes, with electronic properties similar to those of the bulk counterpart, opens opportunities for integrating oxide nanoelectronics with silicon-based architectures.
Info
Ricci Erlandsen, Rasmus Tindal Dahm, Felix Trier, Mario Scuderi, Emiliano Di Gennaro, Alessia Sambri, Charline Kaisa, Reffeldt Kirchert, Nini Pryds, Fabio Miletto Granozio, Thomas Sand Jespersen*. A Two-Dimensional Superconducting Electron Gas in Freestanding LaAlO3/SrTiO3 Micromembranes, Nano Letters (2022)
DOI: https://doi.org/10.1021/acs.nanolett.2c00992
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