Tailoring the Doping Mechanisms at Oxide Interfaces in Nanoscale.

Here, we demonstrate the nanoscale manipulations of two types of charge transfer to the LaAlO/SrTiO interfaces: one from surface adsorbates and another from oxygen vacancies inside LaAlO films. This method can be used to produce multiple insulating and metallic interface states with distinct carrier properties that are highly stable in air. By reconfiguring the patterning and comparing interface structures formed from different doping sources, effects of extrinsic and intrinsic material characters on the transport properties can be distinguished. In particular, a multisubband to single-subband transition controlled by the structural phases in SrTiO was revealed. In addition, the transient behaviors of nanostructures also provided a unique opportunity to study the nanoscale diffusions of adsorbates and oxygen vacancies in oxide heterostructures. Knowledge of such dynamic processes is important for nanodevice implementations.