New phase of superconducting NbN stabilized by heteroepitaxial film growth

Abstract

Thin films of a new, metastable phase of superconducting niobium nitride have been grown using pulsed laser deposition (PLD). This new NbN phase is stabilized by heteroepitaxial growth on (100) MgO and is shown to be a primitive cubic (Pm3m) distortion from the typical B1, or rocksalt structure. Structural and electrical characterization reveals that this NbN phase has a higher-superconducting critical temperature and a larger lattice parameter when compared with films of B1-NbN. Growth of this new phase demonstrates that PLD can be used as a synthesis tool to deposit new, metastable materials.