Chinese scientists have shattered long-held beliefs about certain three-dimensional crystals by discovering and controlling ultratiny "linear" walls inside them, whose thickness and width are around one hundred-thousandth the diameter of a human hair.

The study, led by scientists from the Institute of Physics of the Chinese Academy of Sciences, opens the door to more efficient artificial intelligence chips through storage devices with densities hundreds of times greater than the best currently available. Their results were published in the journal Science on Friday.

To understand this discovery, picture the interior of fluorite ferroelectric crystals — a widely-used material in the microelectronic industry since the 2010s — as a three-dimensional grid like a Rubik's cube. Each small "block" in this grid can store data, controlled by external electric fields. To boost storage density and reduce power consumption, the physical world suggests that the flat, two-dimensional domain walls, which are the boundaries between these "blocks," can also be utilized for data storage.

Having dedicated eight years to studying these types of crystals, the research team found that the segments of their unique layered structure, which were thought to be surface-like charged domain walls, are actually single lines — roughly the width of a single atom on the angstrom scale. In simple terms, what was once thought to be a sheet can, under the right conditions, become a line.

Even more surprisingly, the study showed that these ultrathin lines can remain stable, a vital premise for data storage. Normally, such boundaries would quickly disappear due to electrical forces. However, the team found that tiny defects in the material — missing or extra oxygen atoms — act like glue, holding the charged line in place.

Using advanced electron microscopes, the researchers were able to observe these structures at the atomic scale and even control them by applying localized electric fields. This means that the lines can be created, shifted, or erased on demand, laying the theoretical foundation for data storage.

"Modern data storage devices, from hard drives to solid-state memory, record information using areas measured in tens of nanometers. The newly discovered structures are tens of times smaller. In theory, replacing today's storage units with these atomic-scale features could dramatically increase how much information fits into a tiny space," said Zhong Hai, first author of the study and an associate professor at Ludong University in Shandong province.

It is estimated that a device using such structures could store around 600 times more data than current technologies, potentially packing 20 terabytes of information into an area of one square centimeter — enough for 10,000 high-definition movies to fit into an area the size of a postage stamp.

Zhong also highlighted their significant implications for artificial intelligence hardware, noting that these structures can meet the demand for vast information processing and enable future chips to become denser, faster, and more energy-efficient.

However, Zhong emphasized that this work is fundamental research rather than a commercial product, and practical applications are still years away. He mentioned challenges such as the electrode design to regulate local electrical fields, which are not accessible in everyday settings.

"Nevertheless, this research opens a new path in materials science by redefining how small and flexible information-carrying structures within solids can be," he added.