OPTICAL-PROPERTIES OF ALN

We have performed calculations of the anisotropic frequency dependent dielectric function of AlN, using the linear muffin-tin orbital method within the atomic sphere approximation (LMTO-ASA). Our calculations s how that the anisotropy is very small. The effect of introducing empty spheres is to decrease the energy gap by about 20% and to make the di electric function slightly anisotropic at higher energies. Comparisons with experiments must await experimental results.