Calculated frequencies and Mulliken symbols of zone-centered optical phonon modes of Bi2O2Se and Bi2O2Te. The theoretical frequencies in other works by Pereira37 and Cheng38 are also listed for comparison. Raman or IR activity of each mode is also indicated by “Raman” and “IR”. The unit of the phonon frequency is cm−1.
| Symmetry | Bi2O2Se | Bi2O2Te | Activity | |||
|---|---|---|---|---|---|---|
| This work | Pereira37 | Cheng38 | This work | Cheng38 | ||
| Eu | 54.8 | 59.2 | 56.4 | IR | ||
| A2u | 65.0 | 64.5 | 63.3 | IR | ||
| Eg | 67.3 | 72.0 | 67.99 | 69.1 | 67.01 | Raman |
| A1g | 162.9 | 165.7 | 159.89 | 150.4 | 147.48 | Raman |
| Eu | 268.0 | 293.9 | 243.6 | IR | ||
| B1g | 354.3 | 369.4 | 364.02 | 336.0 | 340.33 | Raman |
| A2u | 377.8 | 402.8 | 347.3 | IR | ||
| Eg | 433.3 | 444.0 | 428.68 | 396.1 | 386.15 | Raman |