Thermally activated epitaxy of NbO

Refractory metal compounds are difficult to synthesize due to the extreme thermodynamic windows required, and therefore deconvoluting intrinsic properties from extrinsic effects can be challenging. This work dives into the synthesis and electronic properties of thin films of the refractory metal oxide NbO utilizing ultrahigh growth temperatures. The highlight is the ability to access a ``thermally activated epitaxy'' growth regime at very high temperatures (T > 1000 \ifmmode^\circ\else\textdegree\fi{}C), which enables reproducible synthesis across a wide range of oxygen partial pressures. Using samples grown in this regime, the authors propose the prototypical electrical properties of NbO, for which a consensus has not yet been made in the literature.