Young's double-slit experiment, devised some 200 years ago, is the simplest demonstration of the wave nature of light. Until now, however, no one had been able to carry it out at the atomic scale in a crystal. The research team has now used two neighboring atomic columns in a silicon crystal as a pair of slits, and has shown that the vibration of those atoms can be read directly from the interference fringes that the electrons create.
Advances in scanning transmission electron microscopy (STEM) now allow an ultra-sharp electron beam to be scanned across a crystal while a detailed diffraction pattern is recorded at every probe position. The research team extracted the patterns formed when the probe passed exactly midway between two neighboring silicon atomic columns just 136 pm apart. The pair of atomic columns acted as a double slit and produced clear interference fringes—a version of Young's experiment about ten million times smaller.
The fringes survive only when neighboring atoms vibrate in step with one another, so analyzing them allowed the research team to measure experimentally how closely the thermal vibrations of the two atoms are correlated. The correlation was stronger along the atomic bond than across it, and it barely changed even at 900 K, indicating that the measured quantity reflects the stiffness of the bond itself. Because heat travels through a semiconductor as atomic vibrations, that stiffness is what governs how readily heat passes from one atom to the next. The method therefore could offer a new way to see, bond by bond, where heat flows easily and where it stalls—a step toward better thermal design of semiconductor devices.
Atomic-scale double-slit interference: two neighboring silicon atomic columns 136 pm apart act as a pair of slits for a focused electron probe (bottom). Young's classical experiment used light, with the slits about 1 mm apart (top).
Papers
Journal: Nature
Title: Atomic-scale double-slit interferometry with a focused electron probe
Authors: Koudai Tabata, Takehito Seki, Toma Susi, Ryo Ishikawa, Naoya Shibata
DOI: 10.1038/s41586-026-10914-9