Scientists directly measure charge states of atoms using an atomic force microscope

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Scientists directly measure charge states of atoms using an atomic force microscope

Model of the experimental setup (left). The gold atom is on a substrate covered with a very thin insulating film of sodium chloride, which also stabilizes the charged atom. The atomically-sharp AFM tip is brought into close proximity with the gold atom—up to a minimum distance of about 0.5 nm. The tip, which is mounted on one prong of a tuning fork (not shown) oscillates with amplitudes as small as 0.02 nanometer—which is about one-tenth of an atom’s diameter. Using this setup, the scientists were able to sense the minute differences in the force exerted by a neutral gold atom and a gold atom charged with one additional electron (right).

(PhysOrg.com) -- IBM scientists in collaboration with the University of Regensburg, Germany, and Utrecht University, Netherlands, for the first time demonstrated the ability to measure the charge state of individual atoms using noncontact atomic force microscopy. Measuring with the precision of a single electron charge and nanometer lateral resolution, researchers succeeded in distinguishing neutral atoms from positively or negatively charged ones.

This represents a milestone in nanoscale science and opens up new possibilities in the exploration of nanoscale structures and devices at the ultimate atomic and molecular limits. These results hold potential to impact a variety of fields such as molecular electronics, catalysis or photovoltaics.

As reported in the June 12 issue of Science magazine, Leo Gross, Fabian Mohn and Gerhard Meyer of IBM’s Zurich Research Laboratory in collaboration with colleagues at the University of Regensburg and Utrecht University imaged and identified differently charged individual gold and silver atoms by measuring the tiny differences in the forces between the tip of an atomic force microscope and a charged or uncharged atom located in close proximity below it.

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