Tin One Atom Thick, Stanene, May Be The Future Of Semiconductors
A single layer of tin atoms could be the world's first material to conduct electricity with 100 percent efficiency at room temperature, a team of theoretical physicists led by researchers from the U.S. Department of Energy's SLAC National Accelerator Laboratory and Stanford University said Thursday. When topological insulators are just one atom thick, their edges force electrons to move in defined lanes without any speed limit, said Shoucheng Zhang, team leader and a physics professor at Stanford and the Stanford Institute for Materials and Energy Sciences (SIMES), a joint institute with SLAC.
Like Us on Facebook
The team's work was published recently in Physical Review Letters. As long as they're on the edges or surfaces, the electrons will travel resistance-free, he added. The theoretical physicists named the material "stanene," derived from the Latin name for tin, stannum. "Stanene could increase the speed and lower the power needs of future generations of computer chips, if our prediction is confirmed," Zhang said. Experiments are underway in several laboratories around the world to test that hypothesis.
Zhang and colleagues have been getting researchers to test the electronic properties of a slew of topological insulators — which conduct electricity only on their outside edges or surfaces — over the past 10 years. During that time, they predicted that mercury telluride and several combinations of bismuth, antimony, selenium, and tellurium should be topological insulators. Though they were soon proven right, none of those materials is a perfect conductor of electricity at room temperature, limiting their potential for commercial applications.
But earlier this year, visiting scientist Yong Xu, who is now at Tsinghua University in Beijing, suggested that Zhang's group consider the properties of a single layer of pure tin. "We knew we should be looking at elements in the lower-right portion of the periodic table," Xu said. "All previous topological insulators have involved the heavy and electron-rich elements located there." Their calculations indicated that a single layer of tin would be a topological insulator at and above room temperature, and that adding fluorine atoms to the tin would extend its operating range to at least 100 degrees Celsius, or 212 degrees Fahrenheit.
The first application for this stanene-fluorine combination could be in the wiring that connects the many sections of a microprocessor, allowing electrons to flow freely, Zhang said. Traffic congestion would still occur at on- and off-ramps made of conventional conductors, he said. But stanene wiring should significantly reduce the power consumption and heat production of microprocessors.
What works in theory will prove challenging in practice: Manufacturers must deposit only an atom-thin single layer of tin and keep that single layer intact during high-temperature chip-making processes. "Eventually, we can imagine stanene being used for many more circuit structures, including replacing silicon in the hearts of transistors," Zhang said. "Someday we might even call this area Tin Valley rather than Silicon Valley."
© 2012 iScience Times All rights reserved. Do not reproduce without permission.