Elastic and optical properties of alpha- and kappa-Al2O3

We present theoretical results for various properties of the stable $\ensuremath{\alpha}$ and metastable $\ensuremath{\kappa}$ phase of alumina, in particular elastic and optical properties. Two different computational methods have been used, the dacapo plane-wave-pseudopotential and the full potential linearized muffin tin orbital methods. The calculations are based upon a recent determination of the crystal structure of $\ensuremath{\kappa}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}.$ Comparison between the two methods and available experimental data show that they are both reliable for calculating the ground-state and mechanical properties for this type of complex material.