Electric-Field Control of Quantum Tunneling Regimes in Focused He-Ion-Beam-Irradiated Oxide Interfaces

Abstract

Helium focused ion beam irradiation enables the fabrication of tunnel field-effect transistors based on two-dimensional electron systems (2DESs) at an oxide interface.High resolution scanning transmission electron microscopy and strain mapping reveal localized lattice deformation confined to the irradiated regions, which act as nanoscale potential barriers. The barrier profile can be continuously tuned by electrostatic backgating at low temperature without degrading the electronic properties of the 2DES electrodes. Transport measurements demonstrate controlled access to thermionic emission, direct tunneling, and Fowler-Nordheim tunneling within a single device architecture. These results establish He FIB irradiation as a powerful tool for nanoscale functional engineering of complex-oxide interfaces and provide a platform for exploring gate-tunable quantum tunneling phenomena.