IBM captures image of electric charge in motion

28 Feb 2012

Density-functional theory calculation of the asymmetry of the electric field above a free naphthalocyanine molecule at a distance d = 0.5 nanometers from the molecular plane. Image by IBM Research

IBM appears to have broken major nanophysics ground, as scientists from an IBM Research group in Zurich have captured what is being hailed as the first-ever image of charge distribution in a single molecule.

Scientists Fabian Mohn, Leo Gross, Nikolaj Moll and Gerhard Meyer, who hail from the Physics of Nanoscale Systems group at IBM Research in Zurich, said they have been able to measure for the first time how charge is distributed within a single molecule. Their findings have been published in the journal Nature Nanotechnology.

The scientists said they used a special kind of atomic force microscopy, called Kelvin probe force microscopy, at low temperatures and in an ultra-high vacuum to directly image the charge distribution within a single molecule.

And, according to IBM, this breakthrough will enable fundamental scientific insights into single-molecule switching and bond formation between atoms and molecules. It said the ability to image the charge distribution within functional molecular structures holds great promise for future applications, such as solar photoconversion, energy storage, or molecular scale computing device.

IBM said the new technique was reminiscent of medical imaging techniques, such as the X-ray, MRI or ultrasonography.

Intersection of biology, chemistry and physics – future impact

Michael Crommie, a professor in the Department of Physics at the University of California, Berkeley, said this work would demonstrate an important new capability of being able to directly measure how charge arranges itself within an individual molecule.

“Understanding this kind of charge distribution is critical for understanding how molecules work in different environments. I expect this technique to have an especially important future impact on the many areas where physics, chemistry, and biology intersect,” he said.

Fabian Mohn of the Physics of Nanoscale Systems Group at IBM Research - Zurich. Image courtesy of IBM Research
Fabian Mohn of the Physics of Nanoscale Systems Group at IBM Research – Zurich. Image by IBM Research

Nanoscale physics

Mohn said yesterday that the technique would provide another channel of information that will further enhance our understanding of nanoscale physics.

“It will now be possible to investigate at the single-molecule level how charge is redistributed when individual chemical bonds are formed between atoms and molecules on surfaces,” he said. “This is essential as we seek to build atomic and molecular scale devices.”

Carmel Doyle was a long-time reporter with Silicon Republic