Alladi Ramakrishnan Hall

Avalanche effect in single-electron tunneling networks

Celestine P Lawrence

IMSc, Chennai

Experiments in the Netherlands have demonstrated that multi-electrode nanomaterial networks, wherein the physics of single-electron tunneling (SET) dominates, can realize any Boolean logic gate by configuring the electrode's voltages. It is expected that large-scale networks of the same kind, operating in a massively-parallel fashion, can lead to energy-efficient and “emergent” computing devices. To aid experimentalists in that end, we theoretically investigate the strength of the avalanche effect in SET networks. For a multi-input single-output binary system, the strict-avalanche criterion (SAC) requires that the output bit changes with a 50% probability upon flipping any input bit.
Thermal and quantum fluctuations are often seen in a bad light, as they are known to weaken the nonlinearity and the negative-differential resistance in SET networks. Here, we will discuss a surprising result wherein an optimal amount of fluctuations actually improves the avalanche effect in a SET network. It is understood to be due to broadening of phase transitions in the SET network. We will see that the avalanche effect can be made strong, for any input electrode (irrespective of its distance from the output electrode), by optimizing the potential landscape in the SET network. We shall end with the practical significance of our work for neuromorphic computing and cryptography.