Microwave interactions with strongly correlated oxide

The interaction of high frequency radiation with quantum materials is of great importance in fundamental science and emerging information and communication technologies. We examine the use of vanadium dioxide (VO2), a quantum material well known for its insulator-to-metal transition, in detecting RF signals within the critical 2.4-GHz frequency band. Our experiments show that the electrical resistance of both stoichiometric and off-stoichiometric VO2 films can be modulated by RF wave exposure, even from a distance, that is, in an entirely non-contact manner. Enhancement of the response of these materials can be achieved by increasing the received RF power or minimizing the separation between the sample's channels. Notably, a 5 μm channel gap in VO2 films yields a ∼73% reduction in resistance, with a response time of 16 μs. We then studied trapping of metastable resistance states within the hysteresis region using trains of microwave exposure intervals. A detailed analysis of the electrical resistance modulation kinetics and device geometry suggests that non-thermal electronic excitation effects influence the response of the material. Our results open a new direction to tune the properties of correlated oxides post-synthesis using microwaves as well as a platform for direct transduction of high frequency signals.