Current-Driven Phase Oscillation and

We report the observation of a current-driven metal (M)-insulator (I) phase oscillation in two-terminal devices incorporating individual WxV1-xO2 nanobeams connected to parallel shunt capacitors. The frequency of the phase oscillation reaches above 5 MHz for 1 Im long devices. The M-I phase oscillation, which coincides with the charging/discharging of the capacitor, occurs through the axial drift of a single M-I domain wall driven by Joule heating and the Peltier effect.