A new material proposed by European physicists could be used as a thermal conductor or an insulator - depending on the direction of heat flow. Acting as a heat valve, this material could have a significant impact on the cooling needs of microelectronic circuitry. It could also be used to route heat into microchemical reactors that are currently being developed for high-efficiency chemical synthesis. Just like natural biological molecules such as DNA, the proposed material would be a chain of linked particles - a one-dimensional solid.
The researchers, based in Como, Italy, and Lyon, France, have simulated the vibrations of atoms in a one-dimensional solid. They found that if the vibrations were anharmonic, with their vibration frequency depending on amplitude, heat would be transmitted less efficiently. By taking this observation further and arranging a three-section chain such that the central section was anharmonic and the ends harmonic, the chain would be an insulator. A further step, making one end more flexible than the other, would lead to one-way heat transfer.
Reference
M Terraneo, M Peyrard and G Casati 2002 Controlling the energy flow in nonlinear lattices: a model for a thermal rectifier Phys. Rev. Lett. 88 094302.