In a ground-breaking study, researchers from NYU and the University of Queensland have made germanium, a common semiconductor, superconducting, opening up new possibilities for highly effective electronic and quantum devices.

Scientists have long worked to develop superconducting semiconductors to enable new quantum technologies and to increase the speed and energy efficiency of semiconductors, which are crucial components of computer chips and solar cells. However, maintaining an ideal atomic structure with the required conduction behavior has proven problematic, making it difficult to achieve superconductivity in semiconductor materials like silicon and germanium.

An international team of scientists reports creating a type of germanium that is superconducting, capable of conducting electricity with zero resistance, allowing currents to flow indefinitely without energy loss, in a recently published paper in the journal Nature Nanotechnology. This results in increased operational speed that uses less energy.

According to New York University physicist Javad Shabani, director of NYU's Center of Quantum Information Physics and the university's recently formed Quantum Institute, one of the paper's authors, establishing superconductivity in germanium, which is already widely used in computer chips and fiber optics, could revolutionize scores of consumer goods and industrial technologies.

These materials could serve as the foundation for future quantum circuits, sensors, and low-power cryogenic electronics, all of which require clean interfaces between superconducting and semiconducting regions, according to Peter Jacobson, a physicist at the University of Queensland and one of the paper's authors. Since germanium is already a workhorse material for advanced semiconductor technologies, it is now possible to create scalable, foundry-ready quantum devices by demonstrating that it can also become superconducting under regulated growth conditions.

Group IV elements are valued for their flexibility and durability because they have properties halfway between those of metals and insulators. These qualities also make semiconductor materials like silicon and germanium valuable. To achieve superconductivity in these materials, conducting electrons that couple and travel without resistance must be added through structural modification, which is a challenging atomic-level procedure. In a paper published in Nature Nanotechnology, researchers produced germanium films that were extensively doped with gallium, a procedure that often causes the crystal to become unstable. But by forcing gallium atoms to replace germanium atoms at abnormally high numbers using sophisticated X-ray techniques, scientists stabilized the structure while significantly deforming it. The result is superconductivity at 3.5 Kelvin (−453°F).