By using superconducting materials through which electrons can move without any loss of energy, physicists hope to build quantum devices that would require less power. According to a fundamental property of superconductivity, however, superconductors can’t transmit spin.
If the movement of the electron pairs, called Cooper pairs, is symmetric in relation to each other, then the pair’s spin has to be asymmetric. When they travel through a conventional superconductor, Cooper pairs’ momentum has to be zero and their orbit perfectly symmetrical.
But if you can change the momentum to asymmetric — leaning toward one direction — then the spin can be symmetric.
“We now have a way to control the spin of the transmitted electrons in simple superconducting devices,” said Professor Amir Yacoby from SEAS.
Superconducting materials can imbue non-superconducting materials with their conductive powers simply by being in close proximity. Using this principle, the researchers built a superconducting sandwich, with superconductors on the outside and mercury telluride in the middle.
The team could measure the spin at various points as the electron waves moved through the material. By using an external magnet, the researchers could tune the total spin of the pairs.
“This discovery opens up new possibilities for storing quantum information and for exploring the underlying nature of superconductivity in novel quantum materials,” said Prof Yacoby.
