Understanding the Shape of GeTe Nanocrystals from First Principles

Nanocrystals with
rationally tailored morphologies and properties
are a thriving research field. The phase-change material (PCM) germanium
telluride (GeTe) has recently been synthesized in a plethora of nanocrystalline
forms and morphologies, but a mechanistic understanding of these experimental
findings has been largely missing so far. Here, we present comprehensive
dispersion-corrected density functional theory (DFT-D) simulations
of the low-index crystal facets of GeTe and how they interact with
relevant ligand molecules. These results enable a systematic understanding
of experimental findings regarding GeTe nanocrystals and clarify the
origin of the broad range of particle shapes observed. This study
also affords semiquantitative signposts assisting future synthetic
studies of nanocrystalline PCMs.