Lattice Dynamics Decoded: A Complete Raman Fingerprint for LaInO3
/ Scientific Highlight
LaInO3 (LIO) has attracted growing interest as a substrate for BaSnO3 (BSO), a perovskite oxide prized for its exceptionally high room-temperature electron mobility and optical transparency. LIO's near-perfect lattice match to BSO helps suppress the dislocation scattering that typically limits mobility in epitaxial BSO films, and LIO/BSO interfaces have already been shown to host two-dimensional electron gases and enable high-mobility field-effect transistors. Despite this rising relevance, a detailed understanding of LIO's lattice dynamics has been missing, held back by previous studies working with inferior sample quality. Phonons underpin a material's mechanical, thermal, and optical behavior, making this gap a real obstacle to the rational design of LIO-based devices.
A new study closes this gap by combining polarization-angle resolved Raman spectroscopy on high-quality bulk LIO single crystals grown from the melt at the Leibniz-Institut für Kristallzüchtung (IKZ) with density functional theory (DFT). The work was led by PDI's Jonas Rose together with colleagues from PDI, IKZ, and Swansea University. By backscattering from four crystallographic surface orientations, (100), (010), (001), and (101), and performing a full symmetry analysis of the orthorhombic D2h point group, the team identified 19 of the 24 Raman-active Γ-point phonon modes and assigned each to its correct irreducible representation. A novel multidimensional fitting procedure allowed the relative Raman tensor elements to be extracted from the angular dependence of the scattering intensities, even for modes that strongly overlap in energy and would otherwise be indistinguishable.
DFT calculations complemented the experiments by providing the phonon dispersion, the phonon density of states, and the atomic displacement patterns underlying each Γ-point mode. The calculated mode frequencies and Raman tensor elements agree well with the experimental observations, and explain the absence of the five missing modes in the Raman spectra.
The result is a comprehensive Raman fingerprint for LaInO3, an essential reference for anyone using Raman spectroscopy to assess crystal quality, strain, or domain orientation in LIO substrates and LIO/BSO heterostructures going forward.
Title: Lattice dynamics and complete polarization analysis of Raman-active modes in LaInO3
Authors: J. Rose, H. Nguyen, M. Meißner, Z. Galazka, R. Gillen, O. Brandt, M. Ramsteiner, M. R. Wagner, H. Tornatzky
Source: Phys. Rev. Mater., 10, 094604 (2026)
DOI: 10.1103/frdm-2plg