Semiconductors are the foundation of modern technology while superconductors with their zero electrical resistance could become the basis for future technologies, including quantum computers.
So-called ‘hybrid structures’ — carefully crafted sandwiches made from superconductors and semiconductors — may lead to new quantum effects.
However, convincing observations have remained elusive. Now, researchers have found a way to probe such ‘super-semi sandwiches’ and to reveal what is going on.
Just like in a conventional sandwich that becomes more than the sum of its parts, the combined properties of Al and InAs become modified in super-semi sandwiches. At the interface between the Al superconductor and the InAs semiconductor, the proximity effect spills the superconductivity into the semiconductor creating new quantum states there. However, until now researchers had a hard time studying them because they could not be probed directly because of being concealed by a presence of the Al superconducting layer.
For their experiment, the researchers created a microscopic sandwich made of an aluminium (Al) superconductor on top of an indium-arsenic (InAs) semiconductor. Superconductors are materials that have no electrical resistance. For that to happen, they are cooled down to close to absolute zero temperature. Semiconductors like InAs or silicon can be insulating or conduct electricity depending on their environment and applied electric field.
