WASHINGTON — An international research team comprising scientists from Denmark, China and America developed the first insulating molecule more effectively than a vacuum barrier, making transistors in a computer chip potentially smaller and more powerful.
They reported in a study published on June 6 in the journal Nature their design of an extremely rigid silicon-based molecule under one nanometer in length that can block tunneling conduction at the nanoscale.
The phenomenon called “quantum mechanical tunneling” is the major challenge when the gap between two metal electrodes narrows to the point that electrons are no longer contained by their barriers, causing leakage current. It is a hurdle standing in the way of making transistors smaller, according to the researchers.
“Our molecular strategy represents a new design principle for classic devices, with the potential to support continued miniaturization in the near term,” said Columbia University engineering physicist and the paper’s co-author Latha Venkataraman, who heads the lab where researcher Li Haixing conducted the project’s experimental work.
Molecular synthesis was carried out in a Lab at Columbia’s Department of Chemistry, in partnership with Xiao Shengxiong’s team at Shanghai Normal University.
The synthetic molecule they designed exhibits a comprehensive destructive interference signatures that lead to complete cancellation of tunneling probability, according to the paper’s lead author Marc Garner, a chemist in the University of Copenhagen’s Solomon Lab, which handled the theoretical work.
Destructive quantum interference occurs when the peaks and valleys of two waves are placed exactly out of phase, so that they can annul oscillation.
According to the researchers, electronic waves can be thought of as analogous to sound waves, flowing through barriers just as sound waves “leak” through walls. The unique properties exhibited by the team’s molecule mitigated tunneling without requiring, in this analogy, a thicker wall.
Their silicon-based strategy also presents a potentially more factory-ready solution, since this insulator is compatible with current industry standards.