Optimized lattice constant a, bond length d, buckling constant Δh, and calculated band gap by PBE EPBEg and HSE06 EPBEg methods of BP monolayer without and with surface-functionalization.
| a (Å) | d B–P (Å) | d B–Cl (Å) | d B–Br (Å) | d P–Cl (Å) | d P–Br (Å) | Δh (Å) | E b (eV) | E PBE (eV) | E HSE (eV) | |
|---|---|---|---|---|---|---|---|---|---|---|
| BP | 3.210 | 1.853 | — | — | — | — | 0 | — | 0.887 | 1.399 |
| Cl–BP–Cl | 3.371 | 2.039 | 1.823 | — | 2.042 | — | 0.608 | −5.365 | 1.659 | 2.711 |
| Cl–BP–Br | 3.425 | 2.068 | 1.821 | — | 2.182 | — | 0.605 | −4.689 | 1.426 | 2.446 |
| Br–BP–Cl | 3.414 | 2.057 | — | 1.959 | — | 2.047 | 0.591 | −4.638 | 1.084 | 2.075 |
| Br–BP–Br | 3.467 | 2.087 | — | 1.958 | — | 2.187 | 0.591 | −3.980 | 1.055 | 2.032 |