Nitrogen-doped amorphous molybdenum superconductor

We report a molybdenum superconductor with a transition temperature exceeding 6 K by heteroatom-doping engineering approach, named nitrogen-doped amorphous molybdenum (NAM). In conventional superconductors, electron pairing is mainly attributed to the electron-phonon interactions among the lattice. However, the amorphous molybdenum superconductor without a repeating atomic arrangement produces an increased superconductivity. Furthermore, the stability was verified by the treatment in organic solvents and deionized water, showing promising applications in superconductor devices. As a demonstration, the NAM-based superconducting nanowire single-photon detector exhibits a saturated quantum efficiency (approaching 100%) at an operating temperature of 2.1 K which can be reached by Gifford-McMahon refrigerators.