Structure and properties of tubular structures based on the quaternary misfit layered compound Sm$_{1−x}$Y$_x$S–TaS$_2$

Misfit layered compounds (MLCs) are incommensurate super-lattices made up of two repeating subunits and are promising for different applications due to the possibility of a synergetic combination of the properties of the employed sublayers. A means of fine-tuning a specific MLC is to alloy one of the elements in the system. In this study, quaternary MLCs made of Sm$_{1−x}$Y$_x$S–TaS$_2$ were successfully synthesized and the resulting structures were characterized in detail, with a specific focus on tubular structures. Owing to the small difference between the ionic radii of Sm and Y, the structure of the quaternary MLCs follows the one of pristine SmS–TaS$_2$, irrespective of the degree of alloying and with an anisotropic change of the lattice parameters up to a maximum of 2.7%. Nevertheless, microscopy, spectroscopy, and diffraction techniques allow us to reveal the impact of the composition on important characteristics of the MLC. Notably, for a specific composition, the ratio between the lattice parameters of the two subsystems adopts a value of 3 to 5, which could lead to a transition toward a commensurate superstructure.