Atomic flippers seek tiny ball for pinball fun

2019-03-02 10:17:02

By Jon Evans (Image: ACS) Once a staple of cafes and student bars, pinball has now been sidelined by video games. But in one nanotechnology lab the game is experiencing a revival, thanks to an “atomic pinball machine”. Two “flippers” made from pairs of platinum atoms are made to move back and forth by firing electrons at them. All that is missing is the ball, says Harold Zandvliet at the University of Twente in the Netherlands. Despite the light-hearted description of work, the team says its device is an important advance in atomic-scale engineering. “This pinball machine elegantly shows that even on the scale of a few atoms, a device can be constructed that only operates if an external signal is applied,” Zandvliet told New Scientist. Because atoms are strongly affected by jostling from other particles, it has been unclear whether atom-scale devices could behave in the same way as full-sized machinery. The new flippers are evidence they can. The researchers created the flippers while studying platinum atoms deposited onto a germanium surface and heated to high temperatures. The platinum atoms line up into pairs, called dimers, arranged in long chains. The chains are separated by just 1.6 nanometres, so lines 60 kilometres long can be squeezed into just 1 square centimetre. While examining these lines using a scanning tunnelling microscope (STM), which passes electrons through atoms and molecules to reveal their structure, Zandvliet discovered that some pairs of platinum atoms appeared fuzzy. A closer look showed that was because they were moving. One atom in the pair acts as a pivot while the other swings back and forth, like a pinball flipper. Only when they were skewered by electrons from the microscope did the flippers move. Increasing the strength of the current increased the flipping frequency. Zandvliet and colleagues are currently trying to discover ways to exert more control over the flippers. Such control over atomic-scale structures will be essential if scientists are to shrink machines and computing devices down to the level of individual molecules. Journal reference: Nano Letters (DOI: