Property changes in two-dimensional electride bilayers through compression, sliding, and twisting

Two-dimensional (2D) layered electrides are a new class of 2D materials with interstitial anionic electrons. We report a first-principles study of the Ca2N and Y2C bilayers, well-known 2D electrides. When one of the two layers is translated, rotated horizontally (∼21.8°), or compressed vertically, the electronic and magnetic properties are changed. When pressure is applied perpendicular to the layer plane, the electrons in the interlayer region are not uniformly distributed and localized; this is more pronounced in Y2C than Ca2N. For lateral sliding in the bilayer, the energy barrier of Ca2N is lower than that of Y2C. Sliding changes or breaks the symmetry, changing the energy band structure of the material, and a change in the local spin polarization occurs in the Y2C bilayer. Finally, the investigation of twisted electride bilayers indicates the generation of a Moiré pattern as seen in the scanning tunneling microscopy image of Y2C. Besides, the spin density appears on the surface as well as in the interlayer region. Our study opens the possibility of using electride layers in straintronics and twistronics. [Display omitted] •On compressing the Ca2N or Y2C bilayer, the electrons collected between the layers become more localized.•The Fermi velocity changes because of the change in the electronic structure due to compression.•Lateral sliding results in a change in the local spin polarization of the Y2C bilayer.•By twisting the Y2C bilayer, the spin density is generated not only in the interlayer region but also above the bilayer surface.•Our study opens up the possibility of using electride layers in straintronics and twistronics.