A crystal structure that combines a semiconductor and superconductor is a tantalizing prospect to create energy-efficient computers, or quantum computers, which leverage the unique quantum mechanical properties of superconductors. Superconductors carry current with little to no energy loss, while semiconductors offer the control and versatility that has made them an essential feature of transistor technology.

The challenge is how to combine the two states and make sure you get the best of both electrical worlds – and can still isolate them.

A collaboration between researchers from Cornell and the Paul Scherrer Institute in Switzerland grew a thin film, only a few atomic layers in thickness, of the one of the oldest known superconductors, niobium nitride, on top of gallium nitride, a semiconductor that in recent decades has become a vital component in optical and power electronics. For the first time, the researchers have successfully measured the electronic properties of the junction between the two materials, a crucial step toward creating hybrid superconductor-semiconductor quantum devices.