the absence of a band gap. The proposed carbon spin logic devices get around this shortfall by taking advantage of the magnetoresistance of graphene nanoribbons.
This is exactly where the huge advantage comes in. Said Friedman, “because all the switching is based on currents rather than voltages, interacting as we’ve described, the speeds could potentially be much higher. Normally, we have to wait to charge up the resistance and capacitance (the so-called RC delay), but here it’s all electromagnetic wave propagation. We’re predicting potential Terahertz operation.”
It should be noted that while the graphene nanoribbon magnetoresistance has been experimentally verified, the proposed all-carbon spin logic gates have not yet been built. There is no theoretical reason, said Friedman, why they can’t be built. However, these materials are rather difficult to work with, so producing these logic circuits will be a challenge. But, given the possibility of a thousand-fold increase in computational speed, there will be ample reward for whoever can crack that nut, which means that we should expect to see more work in this area.