Table 2.
Comparision of force fields prediction of elastic constant for silicon crystal and α-quart
| Si elastic constants (GPa) | |||||
|---|---|---|---|---|---|
| Exp88 | DFT | MTP | COMB | ReaxFF | |
| C11 | 165 | 153.1 | 168.1 | 142.5 | 109.3 |
| C12 | 65 | 57.0 | 51.8 | 75.4 | 46.8 |
| C44 | 79.2 | 74.3 | 65.5 | 69.0 | 37.0 |
| RRMSE (%) | 5.7 | 8.0 | 21.5 | ||
| (5.8) | (7.0) | (18.8) | |||
| α-quartz elastic constants (GPa) | ||||
|---|---|---|---|---|
| Exp106 | DFT | MTP | BKS48 | |
| C11 | 86.8 | 84.2 | 83.1 | 90.6 |
| C12 | 7 | 3.3 | 10.6 | 8.1 |
| C13 | 19.1 | 8.26 | 17.8 | 15.2 |
| C14 | −18 | 17.1 | −21.8 | −17.6 |
| C33 | 105.8 | 89.5 | 100.1 | 107.0 |
| C44 | 58.2 | 52.0 | 34.7 | 50.2 |
| C66 | 39.9 | 42.8 | 36.2 | 41.2 |
| RRMSE (%) | 6.1 | 2.4 | ||
| (12.3) | (10.8) | |||
The RRMSE value calculated against DFT data are provided in parentheses. Note that the BKS potential was implemented by optimizing bulk parameters based on the predictions of experimental elastic constants of α-quartz48.