Elasticity of single-crystal calcite by first-principles calculations

The elastic constants of single-crystal calcite (CaCO₃) have been obtained by extensive first-principles calculations based on the density functional theory (DFT). The corresponding shear, bulk and Young's moduli and Poisson's ratio are evaluated using the Voigt-Reuss-Hill scheme. Based on the present DFT results, the large scatters among nine sets of available experimental data are analyzed. It is found that some of the early experimental data (From Voight (1910) to Reddy et al. (1960)) and some of the recent experimental data obtained since 1963 are in excellent coincidence with the present DFT results. The present results are all among the available experimental data except for a shear modulus C₁₄, while more than three elastic parameters of existed empirical models are out of those of all experimental data. Therefore, the present DFT results provide a sounder theoretical foundation for the elastic properties of crystal calcite, which should be helpful for a better understanding of the exceptional physical mechanical behavior of nature materials with calcite as the main ingredient, such as conches.