Voltage-driven mutual phase locking of planar nano-oscillators

Abstract

Phase locking is a common phenomenon related to coupled oscillators that play an important role in various natural and artificial systems. In this study, we analyzed the possibility of dynamically controlling such a phenomenon between Gunn-effect-based planar nanooscillators via an ensemble Monte Carlo (EMC) method. We found that between two oscillators in parallel with each other, there are two coupling paths, which could be opened or closed via structure determined inner-field effect. One of the paths results in in-phase locking, and whereas the other gives rise to anti-phase locking. Furthermore, by combining the inner-field effect and a top-gate effect, one could dynamically control the phase locking via the top gate’s bias. EMC results showed that the transition time from in-phase to anti-phase locking can be less than 0.2 ns. Accompanied by this was a signal-frequency doubling, from approximately 0.33 THz to approximately 0.66 THz. Based on Adler’s theory, we confirmed the phase locking and concluded that the phase-locking transition could not be properly modeled unless electron-scattering noise was included. Moreover, we obtained the locking range and the frequency fluctuation due to electron-transport noise. The proposed method is convenient and may be applied to other electronic oscillators, thereby aiding in developing high-speed beam-steerable THz sources.