  The electronic band structure of crystals is generally influenced by the
periodic arrangement of their constituent atoms. Specifically, the emerging
two-dimensional (2D) layered structures have shown different band structures
with respect to their stacking configurations. Here, based on first-principles
density-functional theory calculations, we demonstrate that the band structure
of the recently synthesized 2D Ca$_2$N electride changes little for the
stacking sequence as well as the lateral interlayer shift. This intriguing
invariance of band structure with respect to geometrical variations can be
attributed to a complete screening of [Ca$_2$N]$^{+}$ cationic layers by
anionic excess electrons delocalized between the cationic layers. The resulting
weak interactions between 2D dressed cationic layers give rise to not only a
shallow potential barrier for bilayer sliding but also an electron-doping
facilitated shear exfoliation. Our findings open a route for exploration of the
peculiar geometry-insensitive electronic properties in 2D electride materials,
which will be useful for future thermally stable electronic applications.
