A recently-developed technique for generating microwaves could
significantly increase the speed of computers.
Microwave signals could enable faster data processing as they
avoid the parasitic losses associated with metal tracks in
conventional chips.
“This is a new process for generating microwaves, where instead
of using the charge on the electron we use the spin magnetic moment
of the electron,” said Dr Alain Nogaret, a physicist at the
University of Bath who developed the technique.
“We use semiconductor devices that produce an inhomogeneous
magnetic field. As we inject a current through this field there is
a spin resonance process which occurs and generates microwaves,”
said Nogaret.
The effect uses a two-dimensional electron system. Nogaret said
GaAs is appropriate, and graphene – a single layer taken from bulk
graphite, which scientists can now produce – can also be used.
Modulating data into the microwave signals could be achieved via
a simple gate.
“We can control the frequency at which the microwave is emitted
by applying a voltage,” said Nogaret. “So the frequency of the
emission will be controlled by a gate voltage, and we can switch on
and off by injecting a current between the drain and the
source.”
“We would embed the transistors inside coplanar waveguides.
These could have antennas, if it’s a matter of transmitting signals
between chips which are far apart, but within the same wafer we
would have a coplanar waveguide,” added Nogaret.
The plan is to use the technology to build a computer with a
defect-tolerant architecture, inspired by HP’s Teramac machine, so
either material or manufacturing inconsistencies can be handled by
changing the ‘wiring’ topology.
The project, which starts in October and involves the
universities of Nottingham, Leeds, St Andrews, is funded by the
Engineering and Physical Sciences Research Council. The University
of Antwerp and the French research institute CNRS are also
participating.