Breaking Molecular Nitrogen under Mild Conditions with an Atomically Clean Lanthanide Surface

A route to break molecular nitrogen (N₂) under mild conditions is demonstrated by N₂ gas cracking on, and incorporation into, lanthanide films. Successful growth of lanthanide nitride thin films, made by evaporation of lanthanides in a partial N₂ atmosphere at room temperature and pressure as low as 10^-4 Torr, is confirmed using X-ray diffraction. In situ conductance measurements of pure lanthanide thin films exposed to N₂ gas show an immediate surface reaction and a slower bulk reaction. Finally, we report partial reversal of the nitrogen incorporation in a lanthanide nitride by cycling vacuum and nitrogen conditions in the sample chamber.