Dielectric Properties of High-k Oxides: Theory and Experiment for Lu2O3

We present a combined experimental and theoretical analysis of the dielectric and vibrational properties of crystalline lutetium oxide in its ground-state bixbyite structure. The vibrational dielectric function of Lu2O3 thin films grown by atomic-layer deposition was studied by infrared transmission and reflectionabsorption spectroscopies, selectively accessing transverse and longitudinal optical frequencies. The static dielectric constant is extracted analyzing the infrared response. We also present first-principles densityfunctional linear-response calculations, which are in close agreement with experiment, and provide insight into the microscopic nature of vibrational spectra and dielectric properties.