Ultraviolet Optical Properties and Electronic Band Structure of Magnesium Oxide

Abstract

New experimental data on the ultraviolet optical properties of single-crystal magnesium oxide are presented in the range 4.0-14.5 eV. Normal-incidence reflectance data exhibit three strong peaks at 7.60, 11.05, and 13.50 eV. The first peak, due to an excition transition at $\Gamma$, shows strong temperature dependence and is resolved as a doublet at 77°K. The empirical pseudopotential method is used to compute the electronic band structure and the imaginary part of the dielectric function as a function of frequency. Comparison between experiment and theory is discussed and the electronic transitions causing the above peaks are identified.