Intrinsic Insulator-Metal Phase Oscillations

Insulator-metal phase oscillations driven by direct voltages in strongly correlated materials, which can naturally emulate nonlinear neural behavior, have hitherto been realized largely as extrinsic charging and discharging cycles of capacitors with limited frequencies. Here, based on an experimentally validated physical phase-field description of the insulator-metal transition, we demonstrate an intrinsic noncapacitive insulator-metal phase oscillation in a prototypical strongly correlated material, VO2, near room temperature, which can be generic in Mott insulators. Such intrinsic phase oscillations exhibit frequencies 1-2 orders of magnitude higher than the typical frequencies of the extrinsic capacitive phase oscillations. They manifest themselves as electronically driven automatic growth and shrinkage of conduction filaments in contrast to the usual suggestion of thermally driven growth. The discovery of intrinsic phase oscillations has important implications for exploring the intrinsic nonlinear electronic dynamics in strongly correlated materials and advances the realization of high-frequency Mott electronic oscillators for neuromorphic computing.