Stacking-sequence-independent band structure and shear exfoliation of two-dimensional electride materials

Abstract

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.

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• Hidden Weyl Fermions in Paramagnetic Electride Y${}_2$C
• Emerging Two-Dimensional Magnetism in Nonmagnetic Electrides Hf2X (X = S, Se, Te)
• Underlying mechanism of charge transfer in Li-doped MgH${}_{16}$ at high pressure
• Interlayer Exchange Interaction Driven Topological Phase Transition in Antiferromagnetic Electride Gd${}_2$O