Fractional Synchronization of Antiferromagnetic Spin Hall Oscillator with External AC Signal

We demonstrate both theoretically and numerically that an antiferromagnetic (AFM) spin Hall oscillator (SHO) biased by a DC current can be synchronized to an external AC signal when the oscillator’s frequency and external signal frequency are in fractional relation. This regime of SHO operation, the so-called fractional synchronization regime, can be achieved by choosing a specific ratio between AC signal frequency and the driving DC current subjected to an SHO. The obtained results could be important for the development of nanoscale terahertz-frequency AFM spintronic devices able to operate in a wide frequency range.