Electrostatic gating of metallic and insulating phases in SmNiO3 ultrathin films

The correlated electron system SmNiO3 exhibits a metal-insulator phase transition at 130 degrees C. Using an ionic liquid as an electric double layer (EDL) gate on three-terminal ultrathin SmNiO3 devices, we investigate gate control of the channel resistance and transition temperature. Resistance reduction is reproducibly observed across both insulating and metallic phases with similar to 25% modulation at room temperature. We show that resistance modulation is predominantly due to electrostatic charge accumulation and not electrochemical doping by control experiments in inert and air environments. We model the resistance behavior and estimate the accumulated sheet density (similar to 1-2 x 10(14) cm(-2)) and EDL capacitance (similar to 12 mu F/cm(2)). (C) 2013 AIP Publishing LLC.