  Mott metal-insulator transitions possess electronic, magnetic, and structural
degrees of freedom promising next generation energy-efficient electronics. We
report a previously unknown, hierarchically ordered state during a Mott
transition and demonstrate correlated switching of functional electronic
properties. We elucidate in-situ formation of an intrinsic supercrystal in a
Ca2RuO4 thin film. Machine learning-assisted X-ray nanodiffraction together
with electron microscopy reveal multi-scale periodic domain formation at and
below the film transition temperature (TFilm ~ 200-250 K) and a separate
anisotropic spatial structure at and above TFilm. Local resistivity
measurements imply an intrinsic coupling of the supercrystal orientation to the
material's anisotropic conductivity. Our findings add an additional degree of
complexity to the physical understanding of Mott transitions, opening
opportunities for designing materials with tunable electronic properties.
