A breakthrough demonstration of heat dissipation at the atomic scale by an international research team could help scientists overcome major technological hurdles in the development of smaller, more powerful electronics.
Heat—produced when a current passes through a conductive material—remains a major obstacle in the continuing development of smaller, faster, more reliable electronic systems. Engineers have long understood how to direct heat away from sensitive areas in larger circuits as quickly and efficiently as possible, but, until now, research has been unable to accurately describe the relationship between heat and electricity at the smallest end of the nanoscale.
Now, a team of researchers from the University of Michigan, U.S., the Autonomous University of Madrid, Spain; and the University of Konstanz, Germany have shown experimentally how the temperature rises in an atomic-scale system, and how this process differs from that at the macroscale. Their results are published in the journal Nature.
“At 20 or 30 nanometers in size, the active regions of today’s transistors have very small dimensions,” lead researcher Pramod Reddy, University of Michigan assistant professor of mechanical engineering and materials science and engineering, said. “However, if industry keeps pace with Moore’s law and continues shrinking the size of transistors to double their density on a circuit, then atomic-scales are not far off.”
“The most important thing then, is to understand the relationship between the heat dissipated and the electronic structure of the device, in the absence of which you can’t really leverage the atomic scale. This work gives insights into that for the first time.”
In macroscale devices, it is understood that electricity travelling through a wire will cause a fairly uniform temperature rise in it and all the electrodes along it. In contrast, however, the research team was able to determine that when the “wire” is a nanometer-sized molecule connecting two electrodes, the temperature rises significantly in only one of those electrodes. Custom-built stable atomic-scale devices and a nanoscale thermometer were created for the project.
“In an atomic-scale device, all the heating is concentrated in one place and less so in other places,” Reddy said.
“The insights obtained from this work enable a deeper understanding of the relationship between heat dissipation and atomic-scale thermoelectric phenomena, which is the conversion of heat into electricity.”
He added that the results from this work validate a heat-dissipation theory proposed by IBM physicist Rolf Landauer over four decades ago.
Computer science and engineering researchers are expected to be working at this tiny scale within the next two decades.