Heat-controlled mini-storage tank with double balance

Controlling heat flows even at the smallest level and thus preventing computer chips from overheating - the Oldenburg physicist Dr Svend-Age Biehs and two colleagues from Paris have come a step closer to achieving this goal. The highlight of their ideas is a material with very special properties.

In a series of papers, the physicists first published the concepts for a diode, a transistor and now finally for a memory. In contrast to the corresponding components in a conventional computer, these newly developed components should not work with electrical current, but with thermal radiation. "This means we now have all the basic components needed to use thermal radiation to process data in principle," says Biehs.

However, he and his colleagues Philippe Ben-Abdallah and Viacheslav Kubytskyi do not intend to replace conventional computers with heat-controlled computers: Rather, these elements are intended to help dissipate waste heat in nanocomponents in a targeted manner or even make it usable. They could also be used to regulate the temperature in scientific experimental set-ups without contact.

A material with very special properties is also central to the design of the memory: vanadium dioxide (VO2), a so-called phase change material that changes from an insulator to a metal when heat is applied. The trio of researchers from the Universities of Oldenburg and Paris-Sud envisage a structure with two parallel miniature plates at a distance barely visible to the naked eye. One plate is made of glass, the other of vanadium dioxide. When there is a temperature difference on the two outer sides of the storage element, heat flows between the plates until equilibrium is reached.

The trick: due to the special properties of VO2, there is not just one, but two possible equilibria - referred to by scientists as stable states - which represent the "0" and "1" of a bit, as in an electrical computer memory. The memory concept was recently published in the journal "Physical Review Letters".

The co-operation between Biehs and his Parisian colleagues has been funded by the German Academic Exchange Service (DAAD) for one and a half years.