Polytypism and superconductivity in the NbSe2–TiSe2 solid solution

Abstract

The metals are in trigonal prismatic and octahedral coordination in NbSe₂ and TiSe₂, respectively, and Ti and Nb are known to mix randomly in some cases, and here we report that the Nb_1−xTi_xSe₂ solid solution with 0 ≤ x ≤ 1 was synthesized via a solid state preparation method at 850 °C. Quench cooling was used. The polycrystalline powders obtained were characterized for their structural and superconducting properties. Single crystal diffraction on crystals taken from a material where x = 0.5 indicates that the formula is as expected and that Ti substitution is on the Nb site, instead of intercalation between the layers. HR-STEM data support our assignments of the polytypes present.