Cascading of Nanomechanical Resonator Logic

Nanomechanical systems have been proposed as an alternative computing platform for high radiation environments, where semiconductor electronics traditionally fail, as well as to allow improved gate densities and energy consumption. While there have been numerous demonstrations of individual nanomechanical logic gates leveraging the Duffing nonlinearity, the development of useful nanomechanical logic circuits depends strongly on the ability to cascade multiple logic gates. Here we show theoretically that cascading nanomechanical logic gates, where the output of one gate is fed into the input of another, is a complex problem due to the transient dynamics of the collective system. These transient behaviours can lead to undesired bit flips, which precludes cascading altogether. We then show that this issue can be circumvented by carefully initialising the system prior to computation. We illustrate these salient features through the modelled dynamics of two cascaded nanomechanical NAND gates.