Macroscale refrigeration by nanoscale electron transport
Peter J. Lowell, Galen C. O'Neil, Jason M. Underwood, Joel N. Ullom
Nano- and Micro- Electromechanical devices (NEMS & MEMS) have become ubiquitous; examples include automobile accelerometers, inkjet printer heads, infrared viewers, and mirrors for image manipulation and projection. Applications fall broadly in the categories of sensors or tools for manipulating light and matter on similar size scales to the miniature devices themselves. Examples of NEMS devices acting on macroscopic scales are rare. In his 1983 lecture Infinitesimal Machinery, Richard Feynman questioned the utility of miniature machines for direct manipulation of the macroscopic world, using the example of a collection of tiny grinders working in concert (Feynman, 1993). He argued specifically that a single macroscopic grinder could serve the same purpose and generally that the potential of miniature objects lies in the individualization of their tasks. Here we demonstrate the ability of solid-state refrigerators with critical dimensions in the nanometer range to manipulate an intensive property, the temperature, of a macroscopic object. Despite Feynmans pessimism, these refrigerators serve a valuable purpose: the addition of a simple, solid-state technique for cooling below pumped 3He temperatures and the first such addition in almost 50 years.