Superconducting junctions with flat bands

Materials where single electrons move slowly and form so-called flat electron bands, have been proposed to have theoretical promise in high-temperature superconductivity. Here, the authors predict how such materials would behave when used in superconducting junctions, which play a key role in quantum computers and other quantum technology applications. With flat-band materials, the current through the junction may increase as superconductivity becomes weaker. In extended junctions, quantum geometry of the flat electronic band is also important to allow current to flow through despite the slowness of the electron motion. The differences to conventional junctions are characteristic for the flat-band state, and understanding them is necessary for applications