Electron-phonon coupling in DyFeO3 revealed by infrared spectroscopy

TL;DR

This study uses polarized infrared spectroscopy to explore the crystal field and phonon behaviors in DyFeO3, revealing anisotropic phonon spectra and coupled phonon-crystal-field excitations, advancing understanding of multiferroic materials.

Contribution

It provides new experimental insights into the phonon and crystal field dynamics of DyFeO3, highlighting anisotropic behaviors and coupled excitations not previously characterized.

Findings

Anisotropic phonon spectrum observed

Unusual temperature dependence of a phonon mode

Evidence of coupled phonon-crystal-field excitation

Abstract

We have investigated crystal field and phonon dynamics of the multiferroic orthoferrite DyFeO$_3$ via polarized infrared spectroscopy. Reflectance of single crystals was measured in the far- to mid-infrared spectral range at range of temperatures from 10-295 K. We observe a strongly anisotropic phonon spectrum which differs from earlier lattice dynamical calculations in its symmetry, as well as a mode with significant and unusual temperature dependence that we interpret as a coupled phonon-crystal-field excitation.