LAUSR

Oxide heterostructures are an attractive platform for incorporation in field-effect transistors (FETs) due to their diverse physical properties which can be tuned by electrostatic gating. We report a top-gated FET based on a SrTiO3 delta-doped structure, which operates down to cryogenic temperatures. The device shows excellent DC characteristics with an on/off ratio greater than 104 and field effect mobility estimated to be 2125 cm2/V s at 2 K. The high field effect mobility was consistent with the Hall mobility and is attributed to the formation of a two-dimensional electron system in the delta-doped layer: two-dimensional gate-tunable Shubnikov-de Haas oscillations confirm this. The achievement of an electron density of 3 × 1012 cm−2 in a gate-tunable geometry allows for the exploration of the interplay between magnetic, ferroelectric, and superconducting properties of SrTiO3 in the quantum limit.