The leader of the collaboration is Professor Justin Ye from Groningen. Ye and his team have been working on the Ising superconducting state, a state they discovered at HFML-FELIX in 2015. This is a special state that can resist magnetic fields that generally destroy superconductivity. In 2019, they created a device comprising a double layer of molybdenum disulfide that could couple the Ising superconductivity states residing in the two layers. Interestingly, the device makes it possible to switch this protection on or off using an electric field, resulting in a superconducting transistor.
The coupled Ising superconductor device sheds light on a long-standing challenge in the field of superconductivity. In 1964, four scientists (Fulde, Ferrell, Larkin, and Ovchinnikov) predicted a special superconducting state that could exist under conditions of low temperature and strong magnetic field, referred to as the FFLO state. In standard superconductivity, electrons travel in opposite directions as Cooper pairs. Since they travel at the same speed, these electrons have a total kinetic momentum of zero. However, in the FFLO state, there is a small speed difference between the electrons in the Cooper pairs, which means that there is a net kinetic momentum.