'Phase-change' materials could enable brain-like computing

The team at Exeter University used ‘phase-change alloys’ that move from an amorphous to fully crystallised state when subject to a current or light pulse.

‘What we are doing is trying to build electronic systems that mimic, in a simple way, the functionality of the basic building blocks of mammalian brains — namely neurons and synapses,’ project lead Prof David Wright of Exeter told The Engineer.

In conventional computers memory and processing units are physically separate, and data has to be continually shunted between the two, creating ‘bottlenecks’.

‘This slows everything down and wastes a lot of power and is the main reason chip manufacturers have moved to multi-core processors,’ Wright said.

The team turned to neurons for inspiration, noting that they make no real distinction between memory and computation. Looking for possible artificial substitutes the researchers came across so-called ‘phase-change materials’ that flip between amorphous and crystal states, in doing so inducing an electrical conductivity difference of up to five orders of magnitude and a large refractive index change.