Drag and heat—sounds like a car race, doesn’t it? It’s all about electronics and some nanoscale work by researchers at McGill University (Montréal, Canada). From the Dec. 7, 2011 McGill news release,
A team of scientists, led by Guillaume Gervais from McGill’s Physics Department and Mike Lilly from Sandia National Laboratories, has engineered one of the world’s smallest electronic circuits. It is formed by two wires separated by only about 150 atoms or 15 nanometers (nm).
The paper is available behind Nature’s paywall or you can view the abstract for Positive and negative Coulomb drag in vertically integrated one-dimensional quantum wires. Excerpted from the abstract,
Electron interactions in and between wires become increasingly complex and important as circuits are scaled to nanometre sizes, or use reduced-dimensional conductors such as carbon nanotubes, nanowiresand gated high-mobility two-dimensional electron systems. This is because the screening of the long-range Coulomb potential of individual carriers is weakened in these systems, which can lead to phenomena such as Coulomb drag, where a current in one wire induces a voltage in a second wire through Coulomb interactions alone.
The news release addresses the Coulomb drag in more accessible (for some of us) language,
This is the first time that anyone has studied how the wires in an electronic circuit interact with one another when packed so tightly together. Surprisingly, the authors found that the effect of one wire on the other can be either positive or negative. This means that a current in one wire can produce a current in the other one that is either in the same or the opposite direction. This discovery, based on the principles of quantum physics, suggests a need to revise our understanding of how even the simplest electronic circuits behave at the nanoscale.
In addition to the effect on the speed and efficiency of future electronic circuits, this discovery could also help to solve one of the major challenges facing future computer design. This is managing the ever-increasing amount of heat produced by integrated circuits.
According to the news release, this discovery could have an impact on a wide range of electronics including smartphones, desktop computers, televisions, and GPS systems. Congratulations to the McGill team: D. Laroche, G. Gervais, M. P. Lilly, and J. L. Reno.