Polarized Temperature Dependent Raman Study of Bi2Te3-Cr2Ge2Te6 heterostructure and the Ferromagnetic Insulator Cr2Ge2Te6

TL;DR

This study uses polarized Raman microscopy to analyze the phonon behavior and magneto-elastic interactions in Bi2Te3-Cr2Ge2Te6 heterostructures, highlighting Cr2Ge2Te6's suitability as a substrate for topological insulators and spintronic applications.

Contribution

It provides the first detailed temperature-dependent Raman analysis of the heterostructure, revealing phonon dynamics and magneto-elastic coupling in Cr2Ge2Te6.

Findings

Temperature dependence of phonons mainly due to anharmonicity

Small magneto-elastic coupling observed

Cr2Ge2Te6 confirmed as a promising substrate for topological insulators

Abstract

Cr2Ge2Te6 has been of interest for decades, as it is one of only a few ferromagnetic insulators. Recently, this material has been revisited due to its potential as a substrate for Bi2Te3, a topological insulator. This enables the possibility of studying the anomalous quantum Hall effect in topological insulators, and a route to novel spintronic devices. To probe the compatibility of these two materials, we use polarized variable temperature Raman microscopy to study Bi2Te3-Cr2Ge2Te6 heterostructure as well as the phonon dynamics of Cr2Ge2Te6. We found the temperature dependence of the Cr2Ge2Te6 phonons results primarily from anharmonicity, though a small magneto-elastic coupling is also observed. Our results confirm the potential of Cr2Ge2Te6 as a substrate for topological insulators.