Systematic study of the influence of different equations of states on the calculation of elastic properties

摘要

In order to test the influence of the choice of the equation of states (EOS) on the elastic properties we calculated the energy-volume dependence for AlN (rocksalt and wurtzite) and SiO_2 (α-quartz and stishovite) using first-principle density-functional theory calculations for very high compression up to V/V_0 = 0.58. We then used the same data, but using different ranges of the data, to fit seven different EOS. In particular, we compare the behavior of Murnaghan EOS, Birch-Murnaghan third- and fourth-order EOS, natural strain third and fourth order, the universal EOS by Vinet and an EOS with a polynomial E-V relation proposed by Teter et al. under high compression.