Researchers have achieved superconductivity in germanium, a common semiconductor, by precisely doping it with gallium atoms. This breakthrough, detailed in a new study, could enable more efficient quantum devices and cryogenic electronics. The material conducts electricity with zero resistance at 3.5 Kelvin.
For decades, scientists have sought to combine the properties of semiconductors like germanium with superconductivity, which allows electric currents to flow without resistance. Germanium, widely used in computer chips and fiber optics, forms the basis of modern electronics, but inducing superconductivity has proven challenging due to the need for precise atomic arrangements.
A team led by researchers from New York University, the University of Queensland, ETH Zurich, and Ohio State University succeeded by using molecular beam epitaxy to incorporate gallium atoms into germanium films. This doping process, guided by advanced X-ray methods, creates a stable crystal structure where gallium substitutes for germanium atoms, enabling electron pairing for superconductivity at 3.5 Kelvin, or about -453 degrees Fahrenheit.
"Establishing superconductivity in germanium... can potentially revolutionize scores of consumer products and industrial technologies," said Javad Shabani, a physicist at New York University and director of its Center for Quantum Information Physics.
The study, published in Nature Nanotechnology in 2025, highlights potential applications in quantum circuits and low-power electronics. Peter Jacobson, a physicist at the University of Queensland, noted that the material allows clean interfaces between superconducting and semiconducting regions, essential for scalable quantum devices. "These materials could underpin future quantum circuits, sensors, and low-power cryogenic electronics," Jacobson said.
Unlike previous approaches that caused crystal defects, this method ensures uniform structures compatible with silicon layers, reducing signal absorption in quantum technologies. David Cardwell at the University of Cambridge described it as potentially transformational for quantum computing, which requires super-cooling. The work received partial support from the US Air Force's Office of Scientific Research.