A Two-Dimensional Superconducting Electron Gas in Freestanding LaAlO3/SrTiO3 Micromembranes

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*

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

Abstract

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.
Original languageEnglish
JournalNano Letters
Volume22
Issue number12
Pages (from-to)4758–4764
Number of pages7
ISSN1530-6984
DOIs
Publication statusPublished - 2022

Keywords

  • LAO/STO heterostructure
  • Freestanding membrane
  • Superconductivity
  • Strain

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