Probing Anomalous Inelastic Scattering in Spin-ice Ho$_2$Ti$_2$O$_7$ through Resonant Raman Spectroscopy

TL;DR

This study investigates the inelastic scattering in Ho$_2$Ti$_2$O$_7$ spin-ice crystals using resonant Raman spectroscopy, revealing anomalous scattering pathways and symmetry-related effects at room temperature.

Contribution

It provides new insights into the resonant inelastic scattering mechanisms and symmetry effects in Ho$_2$Ti$_2$O$_7$ through detailed Raman analysis under various excitation conditions.

Findings

Identification of anomalous scattering pathways

Variation in Raman cross-section with polarization and orientation

Qualitative explanation of scattering anomalies

Abstract

We report on a study of the inelastic scattering properties of (001) and (111) Ho$_2$Ti$_2$O$_7$ single crystals at room temperature. Structural and compositional analysis along with absorption measurement confirms single crystalline phase of all samples. Room temperature polarized Raman measurements were performed on crystals in non-resonant and two different resonant conditions by using six different laser excitation lines. Lorentzian model fitting analysis is performed on all measured spectra in order to identify the difference in the Raman scattering cross-section in resonant and non-resonant conditions. Variations in the fitting parameters on account of different polarization configurations and crystallographic orientations has helped identifying their symmetry if present. Several possible scattering pathways are discussed in order to qualitatively explain the anomalous scattering results in Ho$_2$Ti$_2$O$_7$