  The correlated electron system SmNiO3 exhibits a metal-insulator phase
transition at 130 {\deg}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 observed across both insulating and metallic phases with ~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 en-vironments. We model the
resistance behavior and estimate the accumulated sheet density (~1-2 x 10^14
cm^-2) and EDL capacitance (~12 {\mu}F/cm^2).
