Neutron Resonance Computed Tomography of Tungsten-Ditelluride in Tellurium Flux

Exfoliable single crystals of tungstenditelluride (WTe 2 ) play a critical role in the investigation of novel phenomena in condensed matter physics and the development od nextgeneration electronic devices. Production of this material requires chemically informed synthesis to control crystal size and shape. In-situ imaging of crystal growth experiments has been shown to excel at relating processing conditions to robust spatial data sets. Such experiments are challenging when applied to the synthesis of WTe 2 , given the high reaction temperature, small crystal volumes, and the dense and opaque tellurium (Te) flux. Computed tomography (CT) produces data sets in three dimensions, providing the highest quality description of synthesis environments. Conventional CT based on X-rays is incapable of revealing growth behavior inside highly dense metal fluxes. We demonstrate that neutron resonance CT is well suited to studying the spatial organization of WTe 2 grown in Te flux. These results suggest that WTe 2 crystals occupy both the ingot bulk and the ingot surface, which requires further investigation to determine the nucleation conditions. Descriptors of length and volume of the largest crystals are extracted from the computed volume rendering, which will inform future interrogations of optimizing synthesis for crystal size. This work provides the foundation needed for real-time in-situ observations of flux growth of high-density materials.