Nanoscale control of LaAlO₃/SrTiO₃metal-insulator transition using ultra-low-voltage electron-beam lithography

We describe a method to control the insulator-metal transition at the LaAlO3/SrTiO3 interface using ultra-low-voltage electron beam lithography. Compared to previous reports that utilize conductive atomic force microscope (c-AFM) lithography, this approach can provide comparable resolution (∼10 nm) at write speeds (10 mm/s) that are up to 10 000× faster than c-AFM. The writing technique is nondestructive, and the conductive state is reversible via prolonged exposure to air. Transport properties of representative devices are measured at milli-Kelvin temperatures, where superconducting behavior is observed. We also demonstrate the ability to create conducting devices on graphene/LaAlO3/SrTiO3 heterostructures. The underlying mechanism is believed to be closely related to the same mechanism regulating c-AFM-based methods.