Lattice dynamics and complete polarization analysis of Raman-active modes in LaInO 3

Abstract

In this study, we present a comprehensive analysis of the Raman-active phonon modes in orthorhombic LaInO 3 based on a combination of polarization-angle resolved Raman spectroscopy and density functional theory calculations. By using backscattering from multiple crystallographic surface orientations and employing a full symmetry analysis, we identify and assign most of the Raman-active Γ -point phonons to their irreducible representations of the D 2 h point group. A multidimensional hyperspectral fitting procedure allows us to extract the relative Raman tensor elements from the angular dependence of the scattering intensities, even for strongly overlapping modes. First-principles calculations yield the phonon dispersion along high-symmetry directions, the phonon densities of states, atomic displacement patterns, and Raman tensor elements, which are found to be in good agreement with the experiment.