  Using molecular beam epitaxy (MBE) to grow multi-elemental oxides (MEO) is
generally challenging, partly due to difficulty in stoichiometry control.
Occasionally, if one of the elements is volatile at the growth temperature,
stoichiometry control can be greatly simplified using adsorption-controlled
growth mode. Otherwise, stoichiometry control remains one of the main hurdles
to achieving high quality MEO film growths. Here, we report another kind of
self-limited growth mode, dubbed diffusion-assisted epitaxy, in which excess
species diffuses into the substrate and leads to the desired stoichiometry, in
a manner similar to the conventional adsorption-controlled epitaxy.
Specifically, we demonstrate that using diffusion-assisted epitaxy,
high-quality epitaxial CuCrO$_2$ films can be grown over a wide growth window
without precise flux control using MBE.
