Edge contacts in metal - SrTiO₃ 2-dimensional electron gas

SrTiO₃ (STO) is a promising candidate for spin to charge conversion and state readout in magnetoelectric spin−orbit logic devices, a low power non-volatile alternative to silicon-based devices. We demonstrate a new technique of fabricating metal-STO 2-dimensional electron gas (2DEG) edge contacts in which the 2DEG is induced via hydrogen plasma after contact formation. The metallic 2DEG has electron density as high as 3×10¹⁴ cm⁻² and high mobility exceeding 10⁴ cm²V⁻¹s⁻¹ at low temperature. For contact sizes of 5–35 µm, contact resistance remained constant, consistent with edge contacts. For smaller contact sizes (1–3 µm), contact resistance decreased sharply, suggesting lateral 2DEG extension beneath the metal contact. This technique opens a promising route for defining nanoscale junctions between oxide 2DEGs and ferromagnetic or superconducting metals for spintronic and/or cryogenic device applications.