Controlling heat flow through a nanostructure
Thermoelectric devices, which can harness temperature differences to produce electricity, might be made more efficient thanks to new research on heat propagation through structures called superlattices. The new findings show, unexpectedly, that heat can travel like waves, rather than particles, through these nanostructures: materials made up of layers only a few billionths of a meter in thickness.Heat — the vibration of atoms and molecules in a material — usually travels in a “random walk,” which is difficult to control. The new observations show a very different pattern, called coherent flow, which is more like ripples that move across a pond in an orderly way. This opens the possibility of new materials in which the flow of heat could be precisely tailored — materials that could have important applications. For example, such research might lead to new ways of shedding the heat generated by electronic devices and semiconductor lasers, which hampers...