Memory Stored in a Single Missing Atom

“Each memory cell is defined by a single missing atom—a tiny defect,” explained UChicago PME Assistant Professor Tian Zhong. “This breakthrough allows terabytes of data to be stored within a millimeter-sized cube of material.”

Figure 1. Trillion-Bit Storage in a Tiny Crystal: The Future of Data.

This innovation exemplifies UChicago PME’s interdisciplinary approach, leveraging quantum techniques to transform classical computing. Originally developed for radiation dosimeters—devices that track radiation exposure for hospital workers—this research has now paved the way for revolutionary microelectronic memory storage. Figure 1 shows Trillion-Bit Storage in a Tiny Crystal: The Future of Data.

“We discovered a way to merge solid-state physics from radiation dosimetry with quantum-focused research, even though our work itself is not strictly quantum,” said first author Leonardo França, a postdoctoral researcher in Zhong’s lab. “There is growing demand for advancements in quantum systems, but also a need to enhance the storage capacity of classical non-volatile memories. Our research operates at the intersection of quantum and optical data storage, bridging these two fields.”

From Radiation Dosimetry to Optical Storage

The research originated during Leonardo França’s PhD studies at the University of São Paulo in Brazil, where he focused on radiation dosimeters—devices that track radiation exposure for workers in hospitals, synchrotrons, and other radiation facilities.

“In hospitals and particle accelerators, it’s essential to monitor radiation exposure levels,” said França. “Certain materials have the unique ability to absorb radiation and retain that information for a specific period.”

Harnessing Light to Store Data

França soon became intrigued by how optical techniques—specifically, shining light on materials—could be used to manipulate and "read" stored information.

“When the crystal absorbs enough energy, it releases electrons and holes, which are then trapped by defects,” França explained. “We can retrieve that information by releasing the electrons and reading it through optical means.”

Recognizing its potential for memory storage, França introduced this non-quantum research into Zhong’s quantum lab, fostering an interdisciplinary breakthrough.

“We’re developing a new kind of microelectronic device—a quantum-inspired technology,” said Zhong.

Rare Earth Elements: The Key to Breakthrough Storage

To develop this innovative memory storage technique, the team introduced ions of rare earth elements, also known as lanthanides, into a crystal. Specifically, they used Praseodymium, a rare-earth element, combined with an Yttrium oxide crystal. However, the method they described is versatile and could be applied to various materials, capitalizing on the unique and flexible optical properties of rare earths.

“Rare earths have specific electronic transitions that allow you to select distinct laser excitation wavelengths for optical control, ranging from UV to near-infrared,” explained França.

Trapping Electrons for Data Retention

Unlike traditional dosimeters activated by X-rays or gamma rays, the new storage device is triggered by a simple ultraviolet laser. The laser excites the lanthanides, causing them to release electrons. These electrons are then trapped by the defects in the oxide crystal, such as the empty spaces where a single oxygen atom should be but is missing.

“It’s impossible to find crystals—whether natural or synthetic—that don’t have defects,” França said. “So, we’re taking advantage of these defects.”

A Billion Bits in a Tiny Cube

While crystal defects are commonly used in quantum research to create “qubits” in materials like diamonds or spinels, the UChicago PME team found an alternative application. They were able to control when these defects were charged and when they weren’t. By assigning a charged gap as “one” and an uncharged gap as “zero,” they transformed the crystal into a potent memory storage device, achieving a level of storage efficiency unseen in classical computing.

“With that millimeter-sized cube, we demonstrated that there are at least a billion of these classical memories—traditional memories—based on atoms,” Zhong said.

Source: SciTECHDaily

Cite this article:

Priyadharshini S (2025), “A Trillion Bits in A Tiny Crystal: The Future of Data Storage,” Anatechmaz, pp.110