Light reveals atoms dancing for the first time in 2D materials

Researchers from Cornell and Stanford Universities have, for the first time, directly observed atoms in two-dimensional (2D) moiré materials dynamically twisting and untwisting in response to light. These ultrathin materials, composed of stacked atomic layers, exhibit unusual properties such as superconductivity and magnetism when slightly twisted. Using ultrafast electron diffraction combined with Cornell’s custom-built Electron Microscope Pixel Array Detector (EMPAD), the team captured this rapid atomic motion occurring within a trillionth of a second, revealing that these materials are not static but rhythmically flex and twist under laser pulses. This breakthrough challenges the previous assumption that moiré materials remain fixed once stacked at a certain angle. Instead, the study shows that light can dynamically enhance and control the twisting motion in real time, opening new possibilities for manipulating quantum behaviors in 2D materials. The collaboration leveraged Stanford’s expertise in engineered materials and Cornell’s advanced imaging technology, enabling the first direct visualization of these ultrafast atomic shifts.