For decades, researchers have tried to create semiconductor materials that can also act as superconductors -- materials capable of carrying electric current without resistance. Semiconductors, which form the foundation of modern computer chips and solar cells, could operate far faster and more efficiently if they also possessed superconducting abilities. Yet turning materials like silicon and germanium into superconductors has remained a major challenge, largely because it requires maintaining a delicate atomic arrangement that allows electrons to move freely.
A global team of scientists has now achieved what once seemed out of reach. In a new study published in Nature Nanotechnology, they report creating a form of germanium that exhibits superconductivity. This means it can conduct electricity with zero resistance, allowing electric currents to circulate endlessly without losing energy. Such behavior could dramatically boost the performance of electronic and quantum devices while reducing power consumption.
"Establishing superconductivity in germanium, which is already widely used in computer chips and fiber optics, can potentially revolutionize scores of consumer products and industrial technologies," explains Javad Shabani, a physicist at New York University and director of its Center of Quantum Information Physics and Quantum Institute.
Peter Jacobson, a physicist at the University of Queensland, adds that the findings could accelerate progress in building practical quantum systems. "These materials could underpin future quantum circuits, sensors, and low-power cryogenic electronics, all of which need clean interfaces between superconducting and semiconducting regions," he says. "Germanium is already a workhorse material for advanced semiconductor technologies, so by showing it can also become superconducting under controlled growth conditions there's now potential for scalable, foundry-ready quantum devices."
How Semiconductors Become Superconductors
Germanium and silicon, both group IV elements with diamond-like crystal structures, occupy a unique position between metals and insulators. Their versatility and durability make them central to modern manufacturing. To induce superconductivity in such elements, scientists must carefully alter their atomic structure to increase the number of electrons available for conduction. These electrons then pair up and move through the material without resistance -- a process that is notoriously difficult to fine-tune on the atomic scale.
In the new study, researchers developed germanium films heavily infused with gallium, a softer element commonly used in electronics. This technique, known as "doping," has long been used to modify a semiconductor's electrical behavior. Normally, high levels of gallium destabilize the crystal, preventing superconductivity.
The team overcame this limitation using advanced X-ray methods to guide a refined process that encourages gallium atoms to take the place of germanium atoms in the crystal lattice. Although this substitution slightly distorts the crystal, it preserves its overall stability and allows it to carry current with zero resistance at 3.5 Kelvin (about -453 degrees Fahrenheit), confirming that it had become superconducting.
Precision Tools Unlock Atomic Control
"Rather than ion implantation, molecular beam epitaxy was used to precisely incorporate gallium atoms into the germanium's crystal lattice," says Julian Steele, a physicist at the University of Queensland and a co-author of the study. "Using epitaxy -- growing thin crystal layers -- means we can finally achieve the structural precision needed to understand and control how superconductivity emerges in these materials."
As Shabani notes, "This works because group IV elements don't naturally superconduct under normal conditions, but modifying their crystal structure enables the formation of electron pairings that allow superconductivity."
The study also involved researchers from ETH Zurich and the Ohio State University and received partial support from the US Air Force's Office of Scientific Research (FA9550-21-1-0338). This international effort marks a key step toward integrating superconducting behavior into the very materials that drive today's electronics, potentially reshaping the landscape of computing and quantum technology.