Preparation, characterization and property of (BiS)xTS2-type ternary chalcogenides (T=V, Nb and Ta) with layered composite crystal structure

Single composite crystals of (BiS)xTS2-type ternary chalcogenides (T=V, Nb and Ta) with layered substructures have been prepared by chemical-vapor transport method with NH4Cl as transport agent. The mutually incommensurate composite crystal structures of (BiS)xTS2 have been successfully characterized by the X-ray diffraction and the convergent beam electron diffraction methods using (3+1)-dimensional superspace group symmetry. Temperature dependences of in-plane electrical resistivity of single composite crystals of (BiS)xTS2 have been measured by a standard d.c. four probe method in the range of 1.7–300 K. It has been suggested that the electronic transport properties of (BiS)xTS2 compounds are metallic below room temperature.