Raman scattering study and lattice-dynamics calculations in YTiO3: Precursor of the magnetic phase transition in the phonon anomalies

TL;DR

This study investigates the lattice dynamics and phonon anomalies in YTiO3 using Raman scattering and calculations, revealing how distortions influence its magnetic phase transition.

Contribution

It provides a detailed analysis of lattice vibrations and their role in the magnetic transition, highlighting the interplay between structural distortions and magnetic properties.

Findings

Identification of vibrational modes via Raman scattering

Distinction between GdFeO3-type and Jahn-Teller distortions

Link between lattice distortions and ferromagnetic ground state

Abstract

The origin of the low-temperature ferromagnetic instability in YTiO3 driven by the interplay between lattice, orbital, spin, and charge degrees of freedom is on the background of lattice dynamics. We present a comprehensive study of temperature-dependent polarized Raman scattering in a nearly stoichiometric orthorhombic YTiO3 single crystal. The lattice-dynamics calculations authenticate the assignment for the observed Ag- and B2g-symmetry modes in terms of the atoms vibrational patterns. The obtained results suggest that trigonal GdFeO3-type distortions become unstable against tetragonal Jahn-Teller distortions, leading to the consequent orbital structure refinement and ferromagnetic ground state in YTiO3.