Comparison of the elastic constants and relaxed-ion piezoelectric stress coefficients of hexagonal ZnO calculated by DFPT and those previously reported. Numbers in parentheses are the relative errors (in percent) with respect to our calculated results.
| Our results | Previous calc.a | Previous expt.b | ||
|---|---|---|---|---|
| Elastic constant (GPa) | C 11 | 205 | 226(+10.24) | 209(+1.95) |
| C 12 | 138 | 139(+0.72) | 120(−13.04) | |
| C 13 | 122 | 123(+0.82) | 104(−14.75) | |
| C 33 | 202 | 242(+19.80) | 211(+4.46) | |
| C 44 | 33 | 40(+21.21) | 44(+33.33) | |
| C 66 | 33 | 44(+33.33) | — | |
| Stress coefficients (C m−2) | e 15 | −0.50 | −0.53(+6.00) | −0.37(−26.00) |
| e 31 | −0.74 | −0.67(−9.46) | −0.62(−16.22) | |
| e 33 | 1.41 | 1.28(−9.22) | 0.96(−31.91) | |