Synthesis and phase composition of Cd3As2 Dirac semimetal crystals doped with Cr

In this work we studied variation of structural and microstructural features of Cd${}_3$As${}_2$ compound upon introducing the Cr component. Obtained X-ray diffraction data suggest that parent Cd${}_3$As${}_2$ phase in studied polycrystals conserve both symmetry and volume of the unit crystal cell, implying low solubility limit of Cr (well below 1 at.$\text{\%}$). Instead, addition of Cr results in the appearance of CrAs and pure Cd phases. The latter is detected in the form of inclusions of Cd–Cd${}_3$As${}_2$ eutectic. Obtained data reveal that CrAs phase formation have rather specific mechanism related to As diffusion, as for large Cr-containing regions we observed clear gradient of As and Cr concentration with radial symmetry. Therefore, varying synthesis parameters one may obtain core–shell inclusions containing different Cr–As phases. Combination of results of thermal and microstructural analysis suggests that Cd${}_3$As${}_2$ and CrAs phases are immiscible.