Researchers at the University of Chicago Pritzker School of Molecular Engineering have developed a new technique for classical computer memory storage using crystal defects. This method, which utilizes quantum techniques in a non-quantum context, allows terabytes of data to be stored within a small cube of material only a millimeter in size.
Assistant Professor Tian Zhong from UChicago PME explained that "each memory cell is a single missing atom—a single defect," enabling significant data storage in minimal space. The research was published in the journal Nanophotonics and is based on the Ph.D. work of Leonardo França, now a postdoctoral researcher in Zhong's lab.
França initially explored radiation dosimeters during his studies at the University of São Paulo, devices used to measure radiation exposure levels. He discovered that optical techniques could manipulate and read information stored by these materials. By integrating this knowledge into Zhong's lab, they achieved an innovative approach to classical memory storage.
The team added ions from "rare earth" elements to an oxide crystal due to their versatile optical properties. These rare earths allow specific laser excitation wavelengths for optical control across various regimes. Unlike typical dosimeters activated by X-rays or gamma rays, this storage device uses ultraviolet lasers to stimulate rare earth ions and release electrons trapped by crystal defects.
França noted that "it's impossible to find crystals—in nature or artificial crystals—that don't have defects," and they leveraged these imperfections for their work. By assigning charged gaps as "one" and uncharged gaps as "zero," they transformed the crystal into an efficient memory storage device on an unprecedented scale.
Zhong highlighted that within the millimeter cube, there are about at least a billion classical memories based on atoms. The study titled “All-optical control of charge-trapping defects in rare-earth doped oxides” received funding from the U.S. Department of Energy under Contract No. DE-AC0206CH11357.