Behold the highest-resolution image of atoms ever seen. Cornell University researchers captured a sample from a crystal in three dimensions and magnified it 100 million times, doubling the resolution that earned the same scientists a Guinness World Record in 2018. Their work could help develop materials for designing more powerful and efficient phones, computers and other electronics, as well as longer-lasting batteries.
The researchers obtained the image using a technique called electron ptychography. It involves shooting a beam of electrons, about a billion of them per second, at a target material. The beam moves infinitesimally as the electrons are fired, so they hit the sample from slightly different angles each time—sometimes they pass through cleanly, and other times they hit atoms and bounce around inside the sample on their way out. Cornell physicist David Muller, whose team conducted the recent study, likens the technique to playing dodgeball against opponents who are standing in the dark. The dodgeballs are electrons, and the targets are individual atoms. Though Muller cannot see the targets, he can see where the “dodgeballs” end up, thanks to advanced detectors. Based on the speckle pattern generated by billions of electrons, machine-learning algorithms can calculate where the atoms were in the sample and what their shapes might be.
Previously, electron ptychography had only been used to image extremely flat samples: those merely one to a few atoms thick. The new study, published in Science, now allows it to capture multiple layers tens to hundreds of atoms thick. That makes the technique much more relevant to materials scientists, who typically study the properties of samples with a thickness of about 30 to 50 nanometers. (That range is smaller than the length your fingernails grow in a minute but many times thicker than what electron ptychography could image in the past.) “They can actually look at stacks of atoms now, so it’s amazing,” says Andrew Maiden, an engineer at the University of Sheffield in England, who helped develop ptychography but was not involved with the new study. “The resolution is just staggering.”
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