Figure 1
From: Ab initio electronic properties of dual phosphorus monolayers in silicon
Model schematics. (a) Type-A bilayer system: tetragonal cell (lines), donors (P 1, P 2), periodic images (translucent circles), and effective donor layers (translucent sheets). Varying separation within bilayers (arrows). (b) Second-layer dopant (in-plane) positions: P 1 projection (black circle), coplanar Si atoms (circles), type-A, -B, and -C positions, other monolayers’ atoms’ projections (dashed circles), and periodic boundary (square).