IBM Scientists Image Charge Distribution within a Molecule for First Time

New technique makes it possible to see how charge is distributed in a molecule

2 min read
IBM Scientists Image Charge Distribution within a Molecule for First Time

IBM Zurich has achieved another breakthrough at the nanoscale by demonstrating for the first time the ability to "see" the charge distribution within a single molecule.

To measure the charge distribution, the IBM scientists, who published their work in the jorunal Nature Nanotechnology, used an offspring of Atomic Force Microscopy (AFM) called Kelvin probe force microscopy (KPFM). 

Observers say they expect this development to have a significant impact on a range of applications.

"This work demonstrates an important new capability," says Michael Crommie, Professor in the Department of Physics at the University of California, Berkeley. "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."

“This technique provides another channel of information that will further our understanding of nanoscale physics," explains Fabian Mohn, a member of the research team that made the breakthrough. "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. This is essential as we seek to build atomic and molecular scale devices.”

Among the hoped-for results from this work is a new method for understanding charge separation and charge transport in charge-transfer, or CT, complexes. These CT complexes, which exist at the places where two or more molecules meet and at junctures connecting parts of one large molecule, are where a fraction of the electronic charge is transferred between the molecules, or parts. Gaining a better understanding of how these CT complexes work could aid in the design of molecular-sized transistors that are more energy efficient.

IBM Zurich has been on a bit of a run lately with AFM-related breakthroughs, announcing earlier this month a new ultrasharp silicon carbide tip for an atomic force microscope that is thousands of times more wear-resistant at the nanoscale than previous designs.

In addition to these developments, it was IBM Zurich researchers who in 2009 developed a method for measuring the amount of electric charge in an atom without it being on the surface of a conducting material.  And in the same year, researchers there were the first to make an image of a molecule.

In a sense, this most recent work, which was conducted by the same team of researchers—Mohn, Leo Gross, Nikolaj Moll and Gerhard Meyer—is a combination of both of those earlier developments.



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Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.


If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

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