LDA results are very close to those from RPA, showing the suitability of LDA for estimating second energy derivatives. Results are in units of gigapascal.
C11 | C22 | C33 | C12 | C23 | C13 | BVRH | ||
c-BN | LDA | 997 | 997 | 997 | 101 | 101 | 101 | 402 |
c-BN | RPA | 968 | 968 | 968 | 81 | 81 | 81 | 378 |
h-BN(AA′) | LDA | 923 | 926 | 28 | 174 | 3 | 3 | 138 |
h-BN(AA′) | RPA | 910 | 915 | 29 | 153 | −4 | −5 | 131 |
m-BN | LDA | 751 | 839 | 45 | 156 | 100 | 68 | 160 |
m-BN | RPA | 745 | 830 | 43 | 137 | 90 | 58 | 151 |