Modulation of carrier concentration in strongly correlated oxides offers the unique opportunity to induce Metal−insulator transitions (MITs) between different electronic phases which dramatically change their physical properties . Particularly interesting are strongly correlated high-temperature superconducting cuprates, in which a reversible modulation of their critical temperature transition can be produced by means of an electric field as the external control parameter. Great progress has been made by inducing electrostatic doping through a ferroelectric polarization or by using a dielectric or electrolyte gating . However, ultrathin superconducting layers and large electric fields must be used to observe significant carrier modulation.
We propose an original approach based on the reversible modulation of non-volatile superconducting−insulator phase transition in YBa2Cu3O7-d films, through oxygen diffusion, that offers several technological and scientific breakthroughs as compared with modulations based on pure electrostatic doping. The key advantage the possibility to induce a volume phase transition (not just confined at the vicinity of the interface between the film and the gate electrode but spanning hundreds of nm away from the gate contact). We analyse different device configurations in which the lateral conduction of a bridge is controlled by gate-tuneable vertical and lateral oxygen motion, providing the basis for the design of robust, homogeneous and flexible transistor-like devices (Figure-a), which may operate both at room temperature or exploit their superconducting nature. We analyse the experimental results in light of a theoretical mode, which incorporates thermally activated and electrically driven volume oxygen diffusion (Figure-b)