Investigation of theoretical infrared spectra on microwave dielectric properties of Re₂O₃ (Re = Ho, Er, Tm) ceramics

Abstract

Based on the crystal structure data of Re2O3 (Re = Ho, Er, Tm) ceramics prepared by the solid‐phase reaction method, the theoretical infrared spectra were calculated via the first‐principles method and were first used to investigate the intrinsic influence of microwave dielectric properties. In addition, the phonon spectra, density of states, and electron localization function (ELF) were also calculated to analyze the dynamic stability and bonding properties. Based on the simple damped harmonic oscillator model, the resonant frequency of Re2O3 (Re = Ho, Er, Tm) ceramics in infrared spectrum varied in accordance with the ELF values because the restoring force constant of the elastic term was determined by the bonding properties. The intensity of the resonant peak was determined by the effective charge and decreased as the ELF increased. The full width at half maximum (FWHM) was dominated by the damping coefficient and had no obvious relationship with bond properties. For microwave dielectric properties, the dielectric constant of Re2O3 (Re = Ho, Er, Tm) ceramics was in accordance with the characteristic peak intensity of the theoretical infrared spectra, and the quality factor (Q × ƒ) was mainly determined by FWHM, corresponding to the damping in lattice vibration.