| Calculation Methods | Exchange-Correlation | Energy Band Gap, Eg (eV) | |
| Direct (Γ-Γ) | Indirect (Γ-X) | ||
| FP-LAPW | LDA | 3.23 [11] | 2.78 [11] |
| FP-LAPW | PBE-GGA | 3.45 [11] | 2.93 [11] |
| FP-LAPW | WC-GGA | 3.18 [11] | 2.82 [11] |
| FP-LAPW | EV-GGA | 4.73 [11] | 4.08 [11] |
| FP-LAPW | WC-GGA | - | 2.80 [15] |
| FP-LAPW | EV-GGA | - | 4.12 [15] |
| FP-LAPW | mBJ | - | 4.19 [15] |
| TB-LMTO | LDA | 3.457 [8] | 2.748 [8] |