  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.
