EXPERIMENTAL PROOF OF THE ELECTRONIC CHARGE-TRANSFER MECHANISM IN A YBA2CU3O7-X-BASED FIELD-EFFECT TRANSISTOR

The dynamics of charge transfer in a YBa2Cu3O7+x-based field-effect tr ansistor were studied in the normal state using signal shape analysis and frequency mixing techniques, the latter being the most sensitive m eans of measuring field effect utilized so far. The speed of response was found to be limited only by the RC time constant of the device con figuration (similar to 9 mu sec). Also the electric field modulation o f the channel resistance was unchanged from de to the highest frequenc y achieved in this device, showing the absence of any significant ''sl ow'' component. This observation unambiguously demonstrates that direc t field induced modulation of the charge carrier density plays a major role in the relatively fast electric field effect in metal-oxide supe rconductors.