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

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 similar to 200 mK. Using anisotropic magnetotransport we extract the superconducting phase coherence length xi approximate to 36-80 nm and establish an upper bound on the thickness of the superconducting electron gas d approximate to 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.

Automated summary

This study reports the fabrication of freestanding oxide membranes with metallic conductivity and superconducting phases, which can be used to form devices on silicon substrates, indicating the potential for integrating oxide nanoelectronics with silicon-based architectures.