Mona Zebarjadi

Most cooling devices operate against the natural flow of heat from hot to cold, keeping, for example, something colder than its surrounding. Yet many applications require an already favourable heat transfer from a hot device, such as a computer processor, to be accelerated. 

A team of researchers from the Ohio State University and the University of Virginia has found a way to use metals with a high thermoelectric power factor to create efficient all-solid-state active coolers. In their paper published in the journal Physical Review Applied, the group describes their new approach to cooling electronic devices and how well it worked.

In 1965, Intel co-founder Gordon Moore noticed that the number of transistors per square inch of integrated circuit doubled roughly every two years. Moore’s Law posits that this trend would continue into the foreseeable future — and it has. Certainly the ability to hold a smartphone in the palm of your hand — in the process availing yourself of the computing power of a circa-1990 supercomputer — is a testament to Moore’s prescience.

Thermoelectric devices — which can either generate an electric current from a difference in temperature or use electricity to produce heating or cooling without moving parts — have been explored in the laboratory since the 19th century. In recent years, their efficiency has improved enough to enable limited commercial use, such as in cooling systems built into the seats of automobiles. But more widespread use, such as to harness waste heat from power plants and engines, calls for better materials.

The design of artificial metamaterials that allow “cloaking”—apparent invisibility to acoustic and electromagnetic waves—is more than a party trick. Many applications suggest themselves if one could create cloaking at useful frequencies or in technologically relevant systems. Writing in Physical Review Letters, Bolin Liao and colleagues at Massachusetts Institute of Technology, Cambridge, propose the use of cloaking in semiconductor devices to optimize electron mobility in nanostructured materials.